From 3ce3bcd6e5f63e681cbcc4a570c26af84ab0268a Mon Sep 17 00:00:00 2001
From: "Stephen J. Butler" <stephen.butler@gmail.com>
Date: Fri, 18 Apr 2014 03:22:32 -0500
Subject: [PATCH 1/4] Be more conservative about claim/release USB interface

---
 drivers/libshut.c    |  13 +++++-
 drivers/libshut.h    |   2 +
 drivers/libusb.c     | 103 +++++++++++++++++++++++++++----------------
 drivers/libusb.h     |   2 +
 drivers/usbhid-ups.c |  69 ++++++++++++++++++++---------
 5 files changed, 129 insertions(+), 60 deletions(-)

diff --git a/drivers/libshut.c b/drivers/libshut.c
index 1e2cd8d8cc..66bf88f569 100644
--- a/drivers/libshut.c
+++ b/drivers/libshut.c
@@ -281,6 +281,15 @@ static void align_request(struct shut_ctrltransfer_s *ctrl )
 #endif
 }
 
+int libshut_claim_interface(int upsfd, int interface) {
+	return 0;
+}
+
+int libshut_release_interface(int upsfd, int interface) {
+	return 0;
+}
+
+
 /* On success, fill in the curDevice structure and return the report
  * descriptor length. On failure, return -1.
  * Note: When callback is not NULL, the report descriptor will be
@@ -569,7 +578,9 @@ shut_communication_subdriver_t shut_subdriver = {
 	libshut_get_report,
 	libshut_set_report,
 	libshut_get_string,
-	libshut_get_interrupt
+	libshut_get_interrupt,
+	libshut_claim_interface,
+	libshut_release_interface
 };
 
 /***********************************************************************/
diff --git a/drivers/libshut.h b/drivers/libshut.h
index 48f48bbca9..0dab2ee63e 100644
--- a/drivers/libshut.h
+++ b/drivers/libshut.h
@@ -69,6 +69,8 @@ typedef struct shut_communication_subdriver_s {
 	int StringIdx, char *buf, size_t buflen);
 	int (*get_interrupt)(int upsfd,
 	unsigned char *buf, int bufsize, int timeout);
+	int (*claim_interface)(int upsfd, int interface);
+	int (*release_interface)(int upsfd, int interface);
 } shut_communication_subdriver_t;
 
 extern shut_communication_subdriver_t	shut_subdriver;
diff --git a/drivers/libusb.c b/drivers/libusb.c
index fd8f5b9487..a874e729e3 100644
--- a/drivers/libusb.c
+++ b/drivers/libusb.c
@@ -70,6 +70,45 @@ static inline int matches(USBDeviceMatcher_t *matcher, USBDevice_t *device) {
 	return matcher->match_function(device, matcher->privdata);
 }
 
+static int libusb_claim_interface(usb_dev_handle *udev, int interface) {
+	int retries, res = -1;
+
+	for (retries = 3; retries > 0; --retries) {
+		res = usb_claim_interface(udev, interface);
+		if (res == 0) {
+			upsdebugx(2, "Claimed USB interface");
+			break;
+		} else {
+			upsdebugx(2, "failed to claim USB device: %s", usb_strerror());
+			/* don't run the rest of this scope if
+			 * we're not going to loop again */
+			if (retries <= 0)
+				break;
+		}
+
+#ifdef HAVE_USB_DETACH_KERNEL_DRIVER_NP
+		/* this method requires at least libusb 0.1.8:
+		 * it force device claiming by unbinding
+		 * attached driver... From libhid */
+		if (usb_detach_kernel_driver_np(udev, interface) < 0) {
+			upsdebugx(2, "failed to detach kernel driver from USB device: %s", usb_strerror());
+		} else {
+			upsdebugx(2, "detached kernel driver from USB device...");
+		}
+#endif
+
+		/* wait before trying again */
+		sleep( 5 );
+	}
+
+	if (res == 0) {
+		/* set default interface */
+		usb_set_altinterface(udev, interface);
+	}
+
+	return res;
+}
+
 #define usb_control_msg         typesafe_control_msg
 
 /* On success, fill in the curDevice structure and return the report
@@ -83,9 +122,7 @@ static inline int matches(USBDeviceMatcher_t *matcher, USBDevice_t *device) {
 static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDeviceMatcher_t *matcher,
 	int (*callback)(usb_dev_handle *udev, USBDevice_t *hd, unsigned char *rdbuf, int rdlen))
 {
-#ifdef HAVE_USB_DETACH_KERNEL_DRIVER_NP
-	int retries;
-#endif
+	static int done_init = 0; /* only call usb_init() once */
 	int rdlen1, rdlen2; /* report descriptor length, method 1+2 */
 	USBDeviceMatcher_t *m;
 	struct usb_device *dev;
@@ -93,7 +130,7 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 	usb_dev_handle *udev;
 	struct usb_interface_descriptor *iface;
 
-	int ret, res;
+	int ret, res, claimed;
 	unsigned char buf[20];
 	unsigned char *p;
 	char string[256];
@@ -104,7 +141,10 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 	int		rdlen;
 
 	/* libusb base init */
-	usb_init();
+	if (!done_init) {
+		usb_init();
+		done_init = 1;
+	}
 	usb_find_busses();
 	usb_find_devices();
 
@@ -122,6 +162,7 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 			   supplied matcher */
 
 			/* open the device */
+			claimed = 0;
 			*udevp = udev = usb_open(dev);
 			if (!udev) {
 				upsdebugx(2, "Failed to open device, skipping. (%s)", usb_strerror());
@@ -191,42 +232,19 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 			}
 			upsdebugx(2, "Device matches");
 
-			/* Now we have matched the device we wanted. Claim it. */
-
-#ifdef HAVE_USB_DETACH_KERNEL_DRIVER_NP
-			/* this method requires at least libusb 0.1.8:
-			 * it force device claiming by unbinding
-			 * attached driver... From libhid */
-			retries = 3;
-			while (usb_claim_interface(udev, 0) < 0) {
-
-				upsdebugx(2, "failed to claim USB device: %s", usb_strerror());
-
-				if (usb_detach_kernel_driver_np(udev, 0) < 0) {
-					upsdebugx(2, "failed to detach kernel driver from USB device: %s", usb_strerror());
-				} else {
-					upsdebugx(2, "detached kernel driver from USB device...");
-				}
-
-				if (retries-- > 0) {
-					continue;
-				}
-
-				fatalx(EXIT_FAILURE, "Can't claim USB device [%04x:%04x]: %s", curDevice->VendorID, curDevice->ProductID, usb_strerror());
-			}
-#else
-			if (usb_claim_interface(udev, 0) < 0) {
-				fatalx(EXIT_FAILURE, "Can't claim USB device [%04x:%04x]: %s", curDevice->VendorID, curDevice->ProductID, usb_strerror());
-			}
-#endif
-
-			/* set default interface */
-			usb_set_altinterface(udev, 0);
-
 			if (!callback) {
 				return 1;
 			}
 
+			/* Now we have matched the device we wanted. Claim it. */
+			claimed = (libusb_claim_interface(udev, 0) == 0);
+				
+			if (!claimed) {
+				upsdebugx(2, "Can't claim USB device [%04x:%04x]: %s", curDevice->VendorID, curDevice->ProductID, usb_strerror());
+				goto next_device;
+			}
+
+
 			if (!dev->config) { /* ?? this should never happen */
 				upsdebugx(2, "  Couldn't retrieve descriptors");
 				goto next_device;
@@ -329,9 +347,16 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 			upsdebugx(2, "Found HID device");
 			fflush(stdout);
 
+			usb_release_interface(udev, 0);
+			claimed = 0;
+
 			return rdlen;
 
 		next_device:
+			if (claimed) {
+				usb_release_interface(udev, 0);
+				claimed = 0;
+			}
 			usb_close(udev);
 		}
 	}
@@ -486,5 +511,7 @@ usb_communication_subdriver_t usb_subdriver = {
 	libusb_get_report,
 	libusb_set_report,
 	libusb_get_string,
-	libusb_get_interrupt
+	libusb_get_interrupt,
+	libusb_claim_interface,
+	usb_release_interface
 };
diff --git a/drivers/libusb.h b/drivers/libusb.h
index 66d2633553..6e51dfa9e6 100644
--- a/drivers/libusb.h
+++ b/drivers/libusb.h
@@ -58,6 +58,8 @@ typedef struct usb_communication_subdriver_s {
 	int StringIdx, char *buf, size_t buflen);
 	int (*get_interrupt)(usb_dev_handle *sdev,
 	unsigned char *buf, int bufsize, int timeout);
+	int (*claim_interface)(usb_dev_handle *sdev, int interface);
+	int (*release_interface)(usb_dev_handle *sdev, int interface);
 } usb_communication_subdriver_t;
 
 extern usb_communication_subdriver_t	usb_subdriver;
diff --git a/drivers/usbhid-ups.c b/drivers/usbhid-ups.c
index cdfbad7a71..6a42988b2f 100644
--- a/drivers/usbhid-ups.c
+++ b/drivers/usbhid-ups.c
@@ -618,14 +618,20 @@ int instcmd(const char *cmdname, const char *extradata)
 		value = atol(val);
 	}
 
+	if (comm_driver->claim_interface(udev, 0) != 0) {
+		return STAT_INSTCMD_FAILED;
+	}
+
 	/* Actual variable setting */
 	if (HIDSetDataValue(udev, hidups_item->hiddata, value) == 1) {
 		upsdebugx(5, "instcmd: SUCCEED\n");
 		/* Set the status so that SEMI_STATIC vars are polled */
 		data_has_changed = TRUE;
+		comm_driver->release_interface(udev, 0);
 		return STAT_INSTCMD_HANDLED;
 	}
 
+	comm_driver->release_interface(udev, 0);
 	upsdebugx(3, "instcmd: FAILED\n"); /* TODO: HANDLED but FAILED, not UNKNOWN! */
 	return STAT_INSTCMD_FAILED;
 }
@@ -672,14 +678,20 @@ int setvar(const char *varname, const char *val)
 		value = atol(val);
 	}
 
+	if (comm_driver->claim_interface(udev, 0) != 0) {
+		return STAT_SET_UNKNOWN;
+	}
+
 	/* Actual variable setting */
 	if (HIDSetDataValue(udev, hidups_item->hiddata, value) == 1) {
 		upsdebugx(5, "setvar: SUCCEED\n");
 		/* Set the status so that SEMI_STATIC vars are polled */
 		data_has_changed = TRUE;
+		comm_driver->release_interface(udev, 0);
 		return STAT_SET_HANDLED;
 	}
 
+	comm_driver->release_interface(udev, 0);
 	upsdebugx(3, "setvar: FAILED\n"); /* FIXME: HANDLED but FAILED, not UNKNOWN! */
 	return STAT_SET_UNKNOWN;
 }
@@ -791,35 +803,42 @@ void upsdrv_updateinfo(void)
 #endif
 	/* Get HID notifications on Interrupt pipe first */
 	if (use_interrupt_pipe == TRUE) {
+		if (comm_driver->claim_interface(udev, 0) != 0) {
+			return;
+		}
+
 		evtCount = HIDGetEvents(udev, event, MAX_EVENT_NUM);
 		upsdebugx(1, "Got %i HID objects...", (evtCount >= 0) ? evtCount : 0);
-	} else {
-		evtCount = 0;
-		upsdebugx(1, "Not using interrupt pipe...");
-	}
 
-	/* Process pending events (HID notifications on Interrupt pipe) */
-	for (i = 0; i < evtCount; i++) {
+		/* Process pending events (HID notifications on Interrupt pipe) */
+		for (i = 0; i < evtCount; i++) {
 
-		if (HIDGetDataValue(udev, event[i], &value, poll_interval) != 1)
-			continue;
+			if (HIDGetDataValue(udev, event[i], &value, poll_interval) != 1)
+				continue;
 
-		if (nut_debug_level >= 2) {
-			upsdebugx(2, "Path: %s, Type: %s, ReportID: 0x%02x, Offset: %i, Size: %i, Value: %g",
-				HIDGetDataItem(event[i], subdriver->utab),
-				HIDDataType(event[i]), event[i]->ReportID,
-				event[i]->Offset, event[i]->Size, value);
-		}
+			if (nut_debug_level >= 2) {
+				upsdebugx(2, "Path: %s, Type: %s, ReportID: 0x%02x, Offset: %i, Size: %i, Value: %g",
+					HIDGetDataItem(event[i], subdriver->utab),
+					HIDDataType(event[i]), event[i]->ReportID,
+					event[i]->Offset, event[i]->Size, value);
+			}
 
-		/* Skip Input reports, if we don't use the Feature report */
-		item = find_hid_info(FindObject_with_Path(pDesc, &(event[i]->Path), ITEM_FEATURE));
-		if (!item) {
-			upsdebugx(3, "NUT doesn't use this HID object");
-			continue;
+			/* Skip Input reports, if we don't use the Feature report */
+			item = find_hid_info(FindObject_with_Path(pDesc, &(event[i]->Path), ITEM_FEATURE));
+			if (!item) {
+				upsdebugx(3, "NUT doesn't use this HID object");
+				continue;
+			}
+
+			ups_infoval_set(item, value);
 		}
 
-		ups_infoval_set(item, value);
+		comm_driver->release_interface(udev, 0);
+	} else {
+		evtCount = 0;
+		upsdebugx(1, "Not using interrupt pipe...");
 	}
+
 #ifdef DEBUG
 	upsdebugx(1, "took %.3f seconds handling interrupt reports...\n", interval());
 #endif
@@ -1165,6 +1184,10 @@ static bool_t hid_ups_walk(walkmode_t mode)
 	double		value;
 	int		retcode;
 
+	if (comm_driver->claim_interface(udev, 0) != 0) {
+		return FALSE;
+	}
+
 	/* 3 modes: HU_WALKMODE_INIT, HU_WALKMODE_QUICK_UPDATE and HU_WALKMODE_FULL_UPDATE */
 
 	/* Device data walk ----------------------------- */
@@ -1174,8 +1197,10 @@ static bool_t hid_ups_walk(walkmode_t mode)
 		/* Check if we are asked to stop (reactivity++) in SHUT mode.
 		 * In USB mode, looping through this takes well under a second,
 		 * so any effort to improve reactivity here is wasted. */
-		if (exit_flag != 0)
+		if (exit_flag != 0) {
+			comm_driver->release_interface(udev, 0);
 			return TRUE;
+		}
 #endif
 		/* filter data according to mode */
 		switch (mode)
@@ -1258,6 +1283,7 @@ static bool_t hid_ups_walk(walkmode_t mode)
 		case -ENXIO:		/* No such device or address */
 		case -ENOENT:		/* No such file or directory */
 			/* Uh oh, got to reconnect! */
+			comm_driver->release_interface(udev, 0);
 			hd = NULL;
 			return FALSE;
 
@@ -1318,6 +1344,7 @@ static bool_t hid_ups_walk(walkmode_t mode)
 		}
 	}
 
+	comm_driver->release_interface(udev, 0);
 	return TRUE;
 }
 

From 09df42c202850c25baf5e38311f9230af8353f7d Mon Sep 17 00:00:00 2001
From: "Stephen J. Butler" <stephen.butler@gmail.com>
Date: Fri, 18 Apr 2014 19:14:46 -0500
Subject: [PATCH 2/4] Add compat mode for dvrs that expect udev to be claimed
 after return from open()

---
 drivers/blazer_usb.c    | 4 ++--
 drivers/libshut.c       | 2 +-
 drivers/libshut.h       | 2 +-
 drivers/libusb.c        | 8 +++++---
 drivers/libusb.h        | 2 +-
 drivers/nutdrv_qx.c     | 4 ++--
 drivers/riello_usb.c    | 4 ++--
 drivers/tripplite_usb.c | 4 ++--
 drivers/usbhid-ups.c    | 4 ++--
 9 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/drivers/blazer_usb.c b/drivers/blazer_usb.c
index 7ba4df289c..5cd40b58ca 100644
--- a/drivers/blazer_usb.c
+++ b/drivers/blazer_usb.c
@@ -409,7 +409,7 @@ int blazer_command(const char *cmd, char *buf, size_t buflen)
 	int	ret;
 
 	if (udev == NULL) {
-		ret = usb->open(&udev, &usbdevice, reopen_matcher, NULL);
+		ret = usb->open(&udev, &usbdevice, reopen_matcher, NULL, 1);
 
 		if (ret < 1) {
 			return ret;
@@ -589,7 +589,7 @@ void upsdrv_initups(void)
 	/* link the matchers */
 	regex_matcher->next = &device_matcher;
 
-	ret = usb->open(&udev, &usbdevice, regex_matcher, NULL);
+	ret = usb->open(&udev, &usbdevice, regex_matcher, NULL, 1);
 	if (ret < 0) {
 		fatalx(EXIT_FAILURE,
 			"No supported devices found. Please check your device availability with 'lsusb'\n"
diff --git a/drivers/libshut.c b/drivers/libshut.c
index 66bf88f569..04abd20d87 100644
--- a/drivers/libshut.c
+++ b/drivers/libshut.c
@@ -298,7 +298,7 @@ int libshut_release_interface(int upsfd, int interface) {
  * is accepted, or < 1 if not.
  */
 int libshut_open(int *upsfd, SHUTDevice_t *curDevice, char *device_path,
-	int (*callback)(int upsfd, SHUTDevice_t *hd, unsigned char *rdbuf, int rdlen))
+	int (*callback)(int upsfd, SHUTDevice_t *hd, unsigned char *rdbuf, int rdlen), int claim)
 {
 	int ret, res; 
 	unsigned char buf[20];
diff --git a/drivers/libshut.h b/drivers/libshut.h
index 0dab2ee63e..306c0c963f 100644
--- a/drivers/libshut.h
+++ b/drivers/libshut.h
@@ -59,7 +59,7 @@ typedef struct shut_communication_subdriver_s {
 	int (*open)(int *upsfd,			/* try to open the next available	*/
 		SHUTDevice_t *curDevice,	/* device matching USBDeviceMatcher_t	*/
 		char *device_path,
-		int (*callback)(int upsfd, SHUTDevice_t *hd, unsigned char *rdbuf, int rdlen));
+		int (*callback)(int upsfd, SHUTDevice_t *hd, unsigned char *rdbuf, int rdlen), int claim);
 	void (*close)(int upsfd);
 	int (*get_report)(int upsfd, int ReportId,
 	unsigned char *raw_buf, int ReportSize );
diff --git a/drivers/libusb.c b/drivers/libusb.c
index a874e729e3..955c366997 100644
--- a/drivers/libusb.c
+++ b/drivers/libusb.c
@@ -120,7 +120,7 @@ static int libusb_claim_interface(usb_dev_handle *udev, int interface) {
  * (if any) will be tried, until there are no more devices left.
  */
 static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDeviceMatcher_t *matcher,
-	int (*callback)(usb_dev_handle *udev, USBDevice_t *hd, unsigned char *rdbuf, int rdlen))
+	int (*callback)(usb_dev_handle *udev, USBDevice_t *hd, unsigned char *rdbuf, int rdlen), int claim)
 {
 	static int done_init = 0; /* only call usb_init() once */
 	int rdlen1, rdlen2; /* report descriptor length, method 1+2 */
@@ -347,8 +347,10 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 			upsdebugx(2, "Found HID device");
 			fflush(stdout);
 
-			usb_release_interface(udev, 0);
-			claimed = 0;
+			if (!claim) {
+				usb_release_interface(udev, 0);
+				claimed = 0;
+			}
 
 			return rdlen;
 
diff --git a/drivers/libusb.h b/drivers/libusb.h
index 6e51dfa9e6..2d193edf82 100644
--- a/drivers/libusb.h
+++ b/drivers/libusb.h
@@ -48,7 +48,7 @@ typedef struct usb_communication_subdriver_s {
 	int (*open)(usb_dev_handle **sdevp,	/* try to open the next available	*/
 		USBDevice_t *curDevice,		/* device matching USBDeviceMatcher_t	*/
 		USBDeviceMatcher_t *matcher,
-		int (*callback)(usb_dev_handle *udev, USBDevice_t *hd, unsigned char *rdbuf, int rdlen));
+		int (*callback)(usb_dev_handle *udev, USBDevice_t *hd, unsigned char *rdbuf, int rdlen), int claim);
 	void (*close)(usb_dev_handle *sdev);
 	int (*get_report)(usb_dev_handle *sdev, int ReportId,
 	unsigned char *raw_buf, int ReportSize );
diff --git a/drivers/nutdrv_qx.c b/drivers/nutdrv_qx.c
index f27e89b333..c119ce72c0 100644
--- a/drivers/nutdrv_qx.c
+++ b/drivers/nutdrv_qx.c
@@ -1610,7 +1610,7 @@ void	upsdrv_initups(void)
 		/* Link the matchers */
 		regex_matcher->next = &device_matcher;
 
-		ret = usb->open(&udev, &usbdevice, regex_matcher, NULL);
+		ret = usb->open(&udev, &usbdevice, regex_matcher, NULL, TRUE);
 		if (ret < 0) {
 			fatalx(EXIT_FAILURE,
 				"No supported devices found. Please check your device availability with 'lsusb'\n"
@@ -1729,7 +1729,7 @@ static int	qx_command(const char *cmd, char *buf, size_t buflen)
 	#endif	/* QX_SERIAL */
 
 		if (udev == NULL) {
-			ret = usb->open(&udev, &usbdevice, reopen_matcher, NULL);
+			ret = usb->open(&udev, &usbdevice, reopen_matcher, NULL, TRUE);
 
 			if (ret < 1) {
 				return ret;
diff --git a/drivers/riello_usb.c b/drivers/riello_usb.c
index 89909da5f8..445bdbe8de 100644
--- a/drivers/riello_usb.c
+++ b/drivers/riello_usb.c
@@ -312,7 +312,7 @@ int riello_command(uint8_t *cmd, uint8_t *buf, uint16_t length, uint16_t buflen)
 	int ret;
 
 	if (udev == NULL) {
-		ret = usb->open(&udev, &usbdevice, reopen_matcher, NULL);
+		ret = usb->open(&udev, &usbdevice, reopen_matcher, NULL, 1);
 
 		if (ret < 1) {
 			return ret;
@@ -759,7 +759,7 @@ void upsdrv_initups(void)
 	/* link the matchers */
 	regex_matcher->next = &device_matcher;
 
-	ret = usb->open(&udev, &usbdevice, regex_matcher, NULL);
+	ret = usb->open(&udev, &usbdevice, regex_matcher, NULL, 1);
 	if (ret < 0) {
 		fatalx(EXIT_FAILURE,
 			"No supported devices found. Please check your device availability with 'lsusb'\n"
diff --git a/drivers/tripplite_usb.c b/drivers/tripplite_usb.c
index e907c124df..8fa0ef3f8b 100644
--- a/drivers/tripplite_usb.c
+++ b/drivers/tripplite_usb.c
@@ -258,7 +258,7 @@ static int reconnect_ups(void)
 	upsdebugx(2, "= device has been disconnected, try to reconnect =");
 	upsdebugx(2, "==================================================");
 
-	ret = comm_driver->open(&udev, &curDevice, reopen_matcher, NULL);
+	ret = comm_driver->open(&udev, &curDevice, reopen_matcher, NULL, 1);
 	if (ret < 1) {
 		upslogx(LOG_INFO, "Reconnecting to UPS failed; will retry later...");
 		dstate_datastale();
@@ -1323,7 +1323,7 @@ void upsdrv_initups(void)
 
 	/* Search for the first supported UPS matching the regular
 	 *            expression */
-	r = comm_driver->open(&udev, &curDevice, regex_matcher, NULL);
+	r = comm_driver->open(&udev, &curDevice, regex_matcher, NULL, 1);
 	if (r < 1) {
 		fatalx(EXIT_FAILURE, "No matching USB/HID UPS found");
 	}
diff --git a/drivers/usbhid-ups.c b/drivers/usbhid-ups.c
index 6a42988b2f..1de26b42f6 100644
--- a/drivers/usbhid-ups.c
+++ b/drivers/usbhid-ups.c
@@ -958,7 +958,7 @@ void upsdrv_initups(void)
 
 	/* Search for the first supported UPS matching the
 	   regular expression (USB) or device_path (SHUT) */
-	ret = comm_driver->open(&udev, &curDevice, subdriver_matcher, &callback);
+	ret = comm_driver->open(&udev, &curDevice, subdriver_matcher, &callback, FALSE);
 	if (ret < 1)
 		fatalx(EXIT_FAILURE, "No matching HID UPS found");
 
@@ -1356,7 +1356,7 @@ static int reconnect_ups(void)
 	upsdebugx(4, "= device has been disconnected, try to reconnect =");
 	upsdebugx(4, "==================================================");
 
-	ret = comm_driver->open(&udev, &curDevice, subdriver_matcher, NULL);
+	ret = comm_driver->open(&udev, &curDevice, subdriver_matcher, NULL, FALSE);
 
 	if (ret > 0) {
 		return 1;

From b09d81538b2efaf5e974866e89c0abe471620d78 Mon Sep 17 00:00:00 2001
From: "Stephen J. Butler" <stephen.butler@gmail.com>
Date: Sat, 19 Apr 2014 00:00:09 -0500
Subject: [PATCH 3/4] Make usbhid-ups more resillient in case of disconnects

---
 drivers/al175.c           |   4 +-
 drivers/apcsmart-old.c    |   4 +-
 drivers/apcsmart.c        |   4 +-
 drivers/apcupsd-ups.c     |   4 +-
 drivers/bcmxcp_io.h       |   2 +-
 drivers/bcmxcp_ser.c      |   4 +-
 drivers/bcmxcp_usb.c      |   4 +-
 drivers/belkin.c          |   4 +-
 drivers/belkinunv.c       |   4 +-
 drivers/bestfcom.c        |   4 +-
 drivers/bestfortress.c    |   4 +-
 drivers/bestuferrups.c    |   4 +-
 drivers/bestups.c         |   4 +-
 drivers/blazer_ser.c      |   4 +-
 drivers/blazer_usb.c      |   4 +-
 drivers/clone-outlet.c    |   4 +-
 drivers/clone.c           |   4 +-
 drivers/dummy-ups.c       |   4 +-
 drivers/etapro.c          |   4 +-
 drivers/everups.c         |   4 +-
 drivers/gamatronic.c      |   3 +-
 drivers/genericups.c      |   4 +-
 drivers/isbmex.c          |   4 +-
 drivers/ivtscd.c          |   4 +-
 drivers/liebert-esp2.c    |   4 +-
 drivers/liebert.c         |   4 +-
 drivers/macosx-ups.c      |   4 +-
 drivers/main.c            |  10 +++-
 drivers/main.h            |   2 +-
 drivers/masterguard.c     |   4 +-
 drivers/metasys.c         |   4 +-
 drivers/mge-shut.c        |   4 +-
 drivers/mge-utalk.c       |   4 +-
 drivers/microdowell.c     |   4 +-
 drivers/netxml-ups.c      |   4 +-
 drivers/nut-ipmipsu.c     |   4 +-
 drivers/nutdrv_atcl_usb.c |   3 +-
 drivers/nutdrv_qx.c       |   4 +-
 drivers/oneac.c           |   4 +-
 drivers/optiups.c         |   4 +-
 drivers/powercom.c        |   7 ++-
 drivers/powerman-pdu.c    |   4 +-
 drivers/powerpanel.c      |   5 +-
 drivers/rhino.c           |   3 +-
 drivers/richcomm_usb.c    |   4 +-
 drivers/riello_ser.c      |   4 +-
 drivers/riello_usb.c      |   4 +-
 drivers/safenet.c         |   4 +-
 drivers/skel.c            |   4 +-
 drivers/snmp-ups.c        |   4 +-
 drivers/solis.c           |   4 +-
 drivers/tripplite.c       |   4 +-
 drivers/tripplite_usb.c   |   4 +-
 drivers/tripplitesu.c     |   4 +-
 drivers/upscode2.c        |   4 +-
 drivers/usbhid-ups.c      | 113 ++++++++++++++++++++++----------------
 drivers/victronups.c      |   4 +-
 57 files changed, 233 insertions(+), 107 deletions(-)

diff --git a/drivers/al175.c b/drivers/al175.c
index 7d0b02e57e..1003b1e7f6 100644
--- a/drivers/al175.c
+++ b/drivers/al175.c
@@ -1261,12 +1261,14 @@ void upsdrv_makevartable(void)
 {
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B9600);
 
 	ser_disable_flow_control();
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/apcsmart-old.c b/drivers/apcsmart-old.c
index 5c06372ee5..1ccd86cfcd 100644
--- a/drivers/apcsmart-old.c
+++ b/drivers/apcsmart-old.c
@@ -1414,7 +1414,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "advorder", "Enable advanced shutdown control");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char	*cable;
 
@@ -1428,6 +1428,8 @@ void upsdrv_initups(void)
 
 	/* make sure we wake up if the UPS sends alert chars to us */
 	extrafd = upsfd;
+
+	return 1;
 }
 
 void upsdrv_help(void)
diff --git a/drivers/apcsmart.c b/drivers/apcsmart.c
index 018b29dd63..849e79c893 100644
--- a/drivers/apcsmart.c
+++ b/drivers/apcsmart.c
@@ -2004,7 +2004,7 @@ void upsdrv_help(void)
 	      );
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char *val;
 	apc_vartab_t *ptr;
@@ -2030,6 +2030,8 @@ void upsdrv_initups(void)
 	/* fill length values */
 	for (ptr = apc_vartab; ptr->name; ptr++)
 		ptr->nlen0 = strlen(ptr->name) + 1;
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/apcupsd-ups.c b/drivers/apcupsd-ups.c
index 1cfc39b32b..125600cd00 100644
--- a/drivers/apcupsd-ups.c
+++ b/drivers/apcupsd-ups.c
@@ -260,7 +260,7 @@ void upsdrv_makevartable(void)
 {
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char *p;
 	struct hostent *h;
@@ -283,6 +283,8 @@ void upsdrv_initups(void)
 	/* TODO: add IPv6 support */
 	host.sin_family=AF_INET;
 	host.sin_port=htons(port);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/bcmxcp_io.h b/drivers/bcmxcp_io.h
index b785a371a5..3d4770cd0f 100644
--- a/drivers/bcmxcp_io.h
+++ b/drivers/bcmxcp_io.h
@@ -12,7 +12,7 @@ void send_write_command(unsigned char *command, int command_length);
 int get_answer(unsigned char *data, unsigned char command);
 int command_read_sequence(unsigned char command, unsigned char *data);
 int command_write_sequence(unsigned char *command, int command_length, unsigned	char *answer);
-void upsdrv_initups(void);
+int upsdrv_initups(void);
 void upsdrv_cleanup(void);
 void upsdrv_reconnect(void);
 void upsdrv_comm_good(void);
diff --git a/drivers/bcmxcp_ser.c b/drivers/bcmxcp_ser.c
index 74cecf9c8e..bcdb1d6985 100644
--- a/drivers/bcmxcp_ser.c
+++ b/drivers/bcmxcp_ser.c
@@ -322,10 +322,12 @@ void pw_comm_setup(const char *port)
 	fatalx(EXIT_FAILURE, "Can't connect to the UPS on port %s!\n", port);
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	pw_comm_setup(device_path);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/bcmxcp_usb.c b/drivers/bcmxcp_usb.c
index 2788029676..ee48bdd7e3 100644
--- a/drivers/bcmxcp_usb.c
+++ b/drivers/bcmxcp_usb.c
@@ -322,9 +322,11 @@ void upsdrv_comm_good(void)
 	nutusb_comm_good();
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsdev = nutusb_open("USB");
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/belkin.c b/drivers/belkin.c
index ad5a658493..aff226a925 100644
--- a/drivers/belkin.c
+++ b/drivers/belkin.c
@@ -466,7 +466,7 @@ void upsdrv_makevartable(void)
 }
 
 /* prep the serial port */
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B2400);
@@ -478,6 +478,8 @@ void upsdrv_initups(void)
 	sleep(1);
 
 	ser_flush_io(upsfd);
+
+	return 1;
 }
 
 void upsdrv_initinfo(void)
diff --git a/drivers/belkinunv.c b/drivers/belkinunv.c
index c5abda2fe7..9e73d43657 100644
--- a/drivers/belkinunv.c
+++ b/drivers/belkinunv.c
@@ -1307,7 +1307,7 @@ void upsdrv_makevartable(void)
 }
 
 /* prep the serial port */
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	/* If '-x wait' or '-x wait=<level>' option given, branch into
 	   standalone behavior. */
@@ -1316,6 +1316,8 @@ void upsdrv_initups(void)
 	}
 
 	belkin_nut_open_tty();
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/bestfcom.c b/drivers/bestfcom.c
index 54ea93ec2f..8deb58ca88 100644
--- a/drivers/bestfcom.c
+++ b/drivers/bestfcom.c
@@ -731,7 +731,7 @@ void upsdrv_init_fc(const char *fcstring)
 	fc.valid = 1;
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char rstring[256];
 
@@ -754,7 +754,7 @@ void upsdrv_initups(void)
 		upsdrv_init_fc(rstring);
 	}
 
-	return;
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/bestfortress.c b/drivers/bestfortress.c
index b12dd15975..45a94cb6eb 100644
--- a/drivers/bestfortress.c
+++ b/drivers/bestfortress.c
@@ -422,7 +422,7 @@ struct {
 	{NULL, B1200},
 };
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	speed_t speed = B1200;
 
@@ -447,6 +447,8 @@ void upsdrv_initups(void)
 	/* the upsh handlers can't be done here, as they get initialized
 	 * shortly after upsdrv_initups returns to main.
 	 */
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/bestuferrups.c b/drivers/bestuferrups.c
index d60cb027d6..20965388f2 100644
--- a/drivers/bestuferrups.c
+++ b/drivers/bestuferrups.c
@@ -397,7 +397,7 @@ static void setup_serial(void)
 }
 
 
-void upsdrv_initups ()
+int upsdrv_initups ()
 {
   char	temp[256], fcstring[512];
 
@@ -488,7 +488,7 @@ void upsdrv_initups ()
   }
 
   fc.valid = 1;
-  return;
+  return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/bestups.c b/drivers/bestups.c
index 854bddf440..92f10d6cf6 100644
--- a/drivers/bestups.c
+++ b/drivers/bestups.c
@@ -426,10 +426,12 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "ID", "Force UPS ID response string");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B2400);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/blazer_ser.c b/drivers/blazer_ser.c
index 7fa72806be..c90f0de623 100644
--- a/drivers/blazer_ser.c
+++ b/drivers/blazer_ser.c
@@ -112,7 +112,7 @@ void upsdrv_makevartable(void)
 }
 
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 #ifndef TESTING
 	const struct {
@@ -183,6 +183,8 @@ void upsdrv_initups(void)
 	usleep(100000);
 #endif
 	blazer_initups();
+
+	return 1;
 }
 
 
diff --git a/drivers/blazer_usb.c b/drivers/blazer_usb.c
index 5cd40b58ca..f5abc7c0a6 100644
--- a/drivers/blazer_usb.c
+++ b/drivers/blazer_usb.c
@@ -513,7 +513,7 @@ void upsdrv_makevartable(void)
 }
 
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 #ifndef TESTING
 	const struct {
@@ -633,6 +633,8 @@ void upsdrv_initups(void)
 	}
 #endif
 	blazer_initups();
+
+	return 1;
 }
 
 
diff --git a/drivers/clone-outlet.c b/drivers/clone-outlet.c
index 99d150cf12..d7b277eaff 100644
--- a/drivers/clone-outlet.c
+++ b/drivers/clone-outlet.c
@@ -385,7 +385,7 @@ void upsdrv_makevartable(void)
 }
 
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char	buf[SMALLBUF];
 	const char	*val;
@@ -405,6 +405,8 @@ void upsdrv_initups(void)
 	prefix.status = xstrdup(buf);
 
 	extrafd = upsfd = sstate_connect();
+
+	return 1;
 }
 
 
diff --git a/drivers/clone.c b/drivers/clone.c
index c8beb830dc..a594c636ec 100644
--- a/drivers/clone.c
+++ b/drivers/clone.c
@@ -545,9 +545,11 @@ void upsdrv_makevartable(void)
 }
 
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	extrafd = upsfd = sstate_connect();
+
+	return 1;
 }
 
 
diff --git a/drivers/dummy-ups.c b/drivers/dummy-ups.c
index 7dbb9910d2..36d9cf1424 100644
--- a/drivers/dummy-ups.c
+++ b/drivers/dummy-ups.c
@@ -218,7 +218,7 @@ void upsdrv_makevartable(void)
 {
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	/* check the running mode... */
 	if (strchr(device_path, '@'))
@@ -234,6 +234,8 @@ void upsdrv_initups(void)
 		mode = MODE_DUMMY;
 		dstate_setinfo("driver.parameter.mode", "dummy");
 	}
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/etapro.c b/drivers/etapro.c
index 6690348600..1742a0b69c 100644
--- a/drivers/etapro.c
+++ b/drivers/etapro.c
@@ -350,7 +350,7 @@ upsdrv_makevartable(void)
 {
 }
 
-void
+int
 upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
@@ -358,6 +358,8 @@ upsdrv_initups(void)
 
 	ser_set_dtr(upsfd, 0);
 	ser_set_rts(upsfd, 1);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/everups.c b/drivers/everups.c
index 7cd9328743..bf70812eb6 100644
--- a/drivers/everups.c
+++ b/drivers/everups.c
@@ -186,13 +186,15 @@ void upsdrv_makevartable(void)
 {
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B300);
 
 	init_serial();
 	InitUpsType();
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/gamatronic.c b/drivers/gamatronic.c
index acc56a3929..dfc0edf297 100644
--- a/drivers/gamatronic.c
+++ b/drivers/gamatronic.c
@@ -365,7 +365,7 @@ void setup_serial(const char *port)
 printf("Connected to UPS on %s baudrate: %d\n",port, baud_rates[i].name);
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	  upsfd = ser_open(device_path);
           setup_serial(device_path);
@@ -401,6 +401,7 @@ void upsdrv_initups(void)
 	 */
 
 
+	  return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/genericups.c b/drivers/genericups.c
index bc8ddc43d6..45e424ab65 100644
--- a/drivers/genericups.c
+++ b/drivers/genericups.c
@@ -290,7 +290,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "sdtime", "Hold time for shutdown value (seconds)");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	struct termios	tio;
 	char	*v;
@@ -329,6 +329,8 @@ void upsdrv_initups(void)
 	if (ioctl(upsfd, TIOCMSET, &upstab[upstype].line_norm)) {
 		fatal_with_errno(EXIT_FAILURE, "ioctl TIOCMSET");
 	}
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/isbmex.c b/drivers/isbmex.c
index 17328b2abe..5ac9125687 100644
--- a/drivers/isbmex.c
+++ b/drivers/isbmex.c
@@ -341,10 +341,12 @@ void upsdrv_makevartable(void)
 {
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B9600);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/ivtscd.c b/drivers/ivtscd.c
index d8ae507dfe..d3e5c4f942 100644
--- a/drivers/ivtscd.c
+++ b/drivers/ivtscd.c
@@ -201,7 +201,7 @@ void upsdrv_makevartable(void)
 {
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	struct termios	tio;
 	const char	*val;
@@ -250,6 +250,8 @@ void upsdrv_initups(void)
 	if (battery.voltage.nom <= battery.voltage.low) {
 		fatalx(EXIT_FAILURE, "Nominal battery voltage must be higher than low battery voltage!");
 	}
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/liebert-esp2.c b/drivers/liebert-esp2.c
index fca7c5e14d..91ded24d1a 100644
--- a/drivers/liebert-esp2.c
+++ b/drivers/liebert-esp2.c
@@ -519,7 +519,7 @@ void upsdrv_makevartable(void)
 	addvar (VAR_VALUE, "baudrate", "serial line speed");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	const char *val = getval("baudrate");
 	speed_t baudrate = B2400;
@@ -549,6 +549,8 @@ void upsdrv_initups(void)
 
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, baudrate);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/liebert.c b/drivers/liebert.c
index b2faa29d4a..459afe268d 100644
--- a/drivers/liebert.c
+++ b/drivers/liebert.c
@@ -172,7 +172,7 @@ void upsdrv_help(void)
 {
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 
@@ -183,6 +183,8 @@ void upsdrv_initups(void)
 
 	/* raise RTS */
 	ser_set_rts(upsfd, 1);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/macosx-ups.c b/drivers/macosx-ups.c
index 11ed475699..bb6204550d 100644
--- a/drivers/macosx-ups.c
+++ b/drivers/macosx-ups.c
@@ -307,7 +307,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "model", "Regular Expression to match power source model name");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	CFArrayRef power_source_key_list;
 	CFIndex num_keys, index;
@@ -428,6 +428,8 @@ void upsdrv_initups(void)
 	/* do stuff */
 
 	CFRelease(power_dictionary);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/main.c b/drivers/main.c
index 7c2fc55f17..674d22c15a 100644
--- a/drivers/main.c
+++ b/drivers/main.c
@@ -606,7 +606,15 @@ int main(int argc, char **argv)
 	/* clear out callback handler data */
 	memset(&upsh, '\0', sizeof(upsh));
 
-	upsdrv_initups();
+	/* loop looking for the UPS. Driver is allowed to not see it
+	 * immediately. */
+	while (!exit_flag) {
+		if (upsdrv_initups())
+			break;
+
+		upslogx(LOG_WARNING, "UPS initialization failed. Retrying after sleep...");
+		sleep(poll_interval);
+	}
 
 	/* UPS is detected now, cleanup upon exit */
 	atexit(upsdrv_cleanup);
diff --git a/drivers/main.h b/drivers/main.h
index 3e3e84eb6e..00fde9f386 100644
--- a/drivers/main.h
+++ b/drivers/main.h
@@ -13,7 +13,7 @@ extern int		upsfd, extrafd, broken_driver, experimental_driver, do_lock_port, ex
 extern unsigned int	poll_interval;
 
 /* functions & variables required in each driver */
-void upsdrv_initups(void);	/* open connection to UPS, fail if not found */
+int upsdrv_initups(void);	/* open connection to UPS, retry if not found */
 void upsdrv_initinfo(void);	/* prep data, settings for UPS monitoring */
 void upsdrv_updateinfo(void);	/* update state data if possible */
 void upsdrv_shutdown(void);	/* make the UPS power off the load */
diff --git a/drivers/masterguard.c b/drivers/masterguard.c
index 7edc899968..1c97481878 100644
--- a/drivers/masterguard.c
+++ b/drivers/masterguard.c
@@ -567,7 +567,7 @@ void upsdrv_makevartable(void)
  * Detects the UPS and handles the command line args.
  * 
  ********************************************************************/
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
     int     count = 0;
     int     fail  = 0;
@@ -608,6 +608,8 @@ void upsdrv_initups(void)
        ser_send_pace(upsfd, UPS_PACE, "%s", "C\x0D" );
        fatalx(EXIT_FAILURE, "Shutdown cancelled");
     }
+
+    return 1;
 }
 
 /********************************************************************
diff --git a/drivers/metasys.c b/drivers/metasys.c
index 647de3c3ce..57e754c865 100644
--- a/drivers/metasys.c
+++ b/drivers/metasys.c
@@ -1036,11 +1036,13 @@ void upsdrv_makevartable(void)
 
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path); 
 	ser_set_speed(upsfd, device_path, B2400); 
 	send_zeros();
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/mge-shut.c b/drivers/mge-shut.c
index 06398edf0e..ff18eb97e1 100644
--- a/drivers/mge-shut.c
+++ b/drivers/mge-shut.c
@@ -290,7 +290,7 @@ void upsdrv_makevartable (void)
 
 /* --------------------------------------------------------------- */
 
-void upsdrv_initups (void)
+int upsdrv_initups (void)
 {
 	upsdebugx(2, "entering upsdrv_initups()");
 
@@ -324,6 +324,8 @@ void upsdrv_initups (void)
 	/* initialise HID communication */
 	if(hid_init_device() != 0)
 		fatalx(EXIT_FAILURE, "Can't initialise HID device");
+
+	return 1;
 }
 
 /* --------------------------------------------------------------- */
diff --git a/drivers/mge-utalk.c b/drivers/mge-utalk.c
index 2935e91d68..94821dcc12 100644
--- a/drivers/mge-utalk.c
+++ b/drivers/mge-utalk.c
@@ -159,7 +159,7 @@ void upsdrv_makevartable(void)
 
 /* --------------------------------------------------------------- */
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char buf[BUFFLEN];
 	int RTS = TIOCM_RTS;
@@ -210,6 +210,8 @@ void upsdrv_initups(void)
 		else
 			upsdebugx(1, "initups: OffDelay unavailable");
 	}
+
+	return 1;
 }
 
 /* --------------------------------------------------------------- */
diff --git a/drivers/microdowell.c b/drivers/microdowell.c
index a1d6605312..06a1508563 100644
--- a/drivers/microdowell.c
+++ b/drivers/microdowell.c
@@ -958,7 +958,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "ups.delay.start", "Override restart delay (10s)");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path) ;
 
@@ -970,6 +970,8 @@ void upsdrv_initups(void)
 	ser_set_rts(upsfd, 0);
 
 	usleep(10000) ; /* small delay (1/100 s)) */
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/netxml-ups.c b/drivers/netxml-ups.c
index 2568ff06f8..4daad2fab1 100644
--- a/drivers/netxml-ups.c
+++ b/drivers/netxml-ups.c
@@ -515,7 +515,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "shutdown_timer", buf);
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	int	ret;
 	char	*val;
@@ -629,6 +629,8 @@ void upsdrv_initups(void)
 	}
 
 	upslogx(LOG_INFO, "Connectivity test: %s", ne_get_error(session));
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/nut-ipmipsu.c b/drivers/nut-ipmipsu.c
index 2991cfc3c8..e6b486b4af 100644
--- a/drivers/nut-ipmipsu.c
+++ b/drivers/nut-ipmipsu.c
@@ -186,7 +186,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "fruid", "FRU identifier to match a specific device"); */
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsdebugx(1, "upsdrv_initups...");
 
@@ -232,6 +232,8 @@ void upsdrv_initups(void)
 	 */
 
 	/* don't try to detect the UPS here */
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/nutdrv_atcl_usb.c b/drivers/nutdrv_atcl_usb.c
index 74244935a3..3e11f57c03 100644
--- a/drivers/nutdrv_atcl_usb.c
+++ b/drivers/nutdrv_atcl_usb.c
@@ -359,7 +359,7 @@ static int usb_device_open(usb_dev_handle **handlep, USBDevice_t *device, USBDev
 /*
  * Initialise the UPS
  */
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	int	i;
 
@@ -383,6 +383,7 @@ void upsdrv_initups(void)
 			"Fatal error: unusable configuration");
 	}
 
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/nutdrv_qx.c b/drivers/nutdrv_qx.c
index c119ce72c0..0676bd17e5 100644
--- a/drivers/nutdrv_qx.c
+++ b/drivers/nutdrv_qx.c
@@ -1429,7 +1429,7 @@ void	upsdrv_initinfo(void)
 }
 
 /* Open the port and the like and choose the subdriver */
-void	upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsdebugx(1, "%s...", __func__);
 
@@ -1666,6 +1666,8 @@ void	upsdrv_initups(void)
 	/* Subdriver initups */
 	if (subdriver->initups != NULL)
 		subdriver->initups();
+
+	return 1;
 }
 
 /* Close the ports and the like */
diff --git a/drivers/oneac.c b/drivers/oneac.c
index 55035f7bbd..510ffac06a 100644
--- a/drivers/oneac.c
+++ b/drivers/oneac.c
@@ -189,7 +189,7 @@ void EliminateLeadingZeroes (const char* buff1, int StringSize, char* buff2,
  * Below are the commands that are called by main				*
  ***************************************************************/
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B9600);
@@ -198,6 +198,8 @@ void upsdrv_initups(void)
 	ser_send_pace(upsfd, 100, "%s", COMMAND_END);
 	ser_send_pace(upsfd, 100, "%s", COMMAND_END);
 	sleep (1);
+
+	return 1;
 }
 
 void upsdrv_initinfo(void)
diff --git a/drivers/optiups.c b/drivers/optiups.c
index 26b7f47797..b5776641dc 100644
--- a/drivers/optiups.c
+++ b/drivers/optiups.c
@@ -540,12 +540,14 @@ void upsdrv_makevartable(void)
 	addvar(VAR_FLAG, OPTI_POWERUP, "(Zinto D) Power-up UPS at start (cannot identify a powered-down Zinto D)");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B2400);
 
 	/* NO PARSED COMMAND LINE VARIABLES */
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/powercom.c b/drivers/powercom.c
index 62d8683f5d..08dbfc2aea 100644
--- a/drivers/powercom.c
+++ b/drivers/powercom.c
@@ -761,7 +761,7 @@ void upsdrv_shutdown(void)
 }
 
 /* initialize UPS */
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	int tmp,model = 0;
 	unsigned int i;
@@ -905,7 +905,7 @@ void upsdrv_initups(void)
 
 	/* Setup Model and LineVoltage */
 	if (!strncmp(types[type].name, "BNT",3) || !strcmp(types[type].name, "KIN") || !strcmp(types[type].name, "IMP") || !strcmp(types[type].name, "OPTI")) {
-		if (!ups_getinfo()) return;
+		if (!ups_getinfo()) return 1;
 		/* Give "BNT-other" a chance! */
 		if (raw_data[MODELNAME]==0x42 || raw_data[MODELNAME]==0x4B || raw_data[MODELNAME]==0x4F){
 			model=BNTmodels[raw_data[MODELNUMBER]/16];
@@ -937,7 +937,7 @@ void upsdrv_initups(void)
 		if (ser_send_char (upsfd, BATTERY_TEST) != 1) {
 			upslogx(LOG_NOTICE, "writing error");
 			dstate_datastale();
-			return;
+			return 1;
 		}
 	}
 	
@@ -978,6 +978,7 @@ void upsdrv_initups(void)
 							types[type].voltage[2], types[type].voltage[3]);
 	}
 
+	return 1;
 }
 
 /* display help */
diff --git a/drivers/powerman-pdu.c b/drivers/powerman-pdu.c
index b7bcf3dab2..a9923a670a 100644
--- a/drivers/powerman-pdu.c
+++ b/drivers/powerman-pdu.c
@@ -165,7 +165,7 @@ void upsdrv_makevartable(void)
 	/* FIXME: anything useful to be put here? */
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	pm_err_t rv = PM_ESUCCESS;
 
@@ -177,6 +177,8 @@ void upsdrv_initups(void)
 
 	/* FIXME: suitable?
 	 * poll_interval = 30; */
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/powerpanel.c b/drivers/powerpanel.c
index c683c3fab0..79506548b1 100644
--- a/drivers/powerpanel.c
+++ b/drivers/powerpanel.c
@@ -147,7 +147,7 @@ void upsdrv_shutdown(void)
 	upslogx(LOG_ERR, "Shutdown command failed!");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char	*version;
 
@@ -170,7 +170,7 @@ void upsdrv_initups(void)
 
 		if (subdriver[mode]->initups() > 0) {
 			upslogx(LOG_INFO, "CyberPower UPS with %s protocol on %s detected", subdriver[mode]->version, device_path);
-			return;
+			return 1;
 		}
 
 		ser_set_dtr(upsfd, 0);
@@ -178,6 +178,7 @@ void upsdrv_initups(void)
 	}
 
 	fatalx(EXIT_FAILURE, "CyberPower UPS not found on %s", device_path);
+	return 0;
 }
 
 void upsdrv_help(void)
diff --git a/drivers/rhino.c b/drivers/rhino.c
index c43c411b1c..dd2e83792e 100644
--- a/drivers/rhino.c
+++ b/drivers/rhino.c
@@ -775,7 +775,7 @@ void upsdrv_makevartable(void)
 
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B19200);
@@ -784,6 +784,7 @@ void upsdrv_initups(void)
 	ser_set_dtr(upsfd, 1);
 	ser_set_rts(upsfd, 0);
 	
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/richcomm_usb.c b/drivers/richcomm_usb.c
index 0b9b8f2742..d4947e230d 100644
--- a/drivers/richcomm_usb.c
+++ b/drivers/richcomm_usb.c
@@ -351,7 +351,7 @@ static int usb_device_open(usb_dev_handle **handlep, USBDevice_t *device, USBDev
 /*
  * Initialise the UPS
  */
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char	reply[REPLY_PACKETSIZE];
 	int	i;
@@ -382,6 +382,8 @@ void upsdrv_initups(void)
 		query_ups(reply);
 		sleep(1);
 	}
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/riello_ser.c b/drivers/riello_ser.c
index b76be96345..3db2dc674a 100644
--- a/drivers/riello_ser.c
+++ b/drivers/riello_ser.c
@@ -939,7 +939,7 @@ void upsdrv_makevartable(void)
 	/* addvar(VAR_VALUE, "foo", "Override foo setting"); */
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsdebugx(2, "entering upsdrv_initups()");
 
@@ -978,6 +978,8 @@ void upsdrv_initups(void)
 	/* don't try to detect the UPS here */
 
 	/* initialise communication */
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/riello_usb.c b/drivers/riello_usb.c
index 445bdbe8de..27181bda04 100644
--- a/drivers/riello_usb.c
+++ b/drivers/riello_usb.c
@@ -698,7 +698,7 @@ void upsdrv_makevartable(void)
 
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	const struct {
 		const char	*name;
@@ -784,6 +784,8 @@ void upsdrv_initups(void)
 
 	dstate_setinfo("ups.vendorid", "%04x", usbdevice.VendorID);
 	dstate_setinfo("ups.productid", "%04x", usbdevice.ProductID);
+
+	return 1;
 }
 
 void upsdrv_initinfo(void)
diff --git a/drivers/safenet.c b/drivers/safenet.c
index 77170fb32d..90fbd9e71f 100644
--- a/drivers/safenet.c
+++ b/drivers/safenet.c
@@ -462,7 +462,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "offdelay", "Delay before UPS shutdown (seconds)");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	struct termios	tio;
 	const char	*val;
@@ -519,6 +519,8 @@ void upsdrv_initups(void)
 	if ((offdelay < 0) || (offdelay > 999)) {
 		fatalx(EXIT_FAILURE, "Shutdown delay '%d' out of range [0..999]", offdelay);
 	}
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/skel.c b/drivers/skel.c
index 5d4b93060e..5b435511fd 100644
--- a/drivers/skel.c
+++ b/drivers/skel.c
@@ -150,7 +150,7 @@ void upsdrv_makevartable(void)
 	/* addvar(VAR_VALUE, "foo", "Override foo setting"); */
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	/* upsfd = ser_open(device_path); */
 	/* ser_set_speed(upsfd, device_path, B1200); */
@@ -184,6 +184,8 @@ void upsdrv_initups(void)
 	 */
 
 	/* don't try to detect the UPS here */
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/snmp-ups.c b/drivers/snmp-ups.c
index e99615d9a0..389c8ce3db 100644
--- a/drivers/snmp-ups.c
+++ b/drivers/snmp-ups.c
@@ -256,7 +256,7 @@ void upsdrv_makevartable(void)
 		"Set the privacy protocol (DES or AES) used for encrypted SNMPv3 messages (default=DES)");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	snmp_info_t *su_info_p;
 	char model[SU_INFOSIZE];
@@ -308,6 +308,8 @@ void upsdrv_initups(void)
 		dstate_addcmd("shutdown.return");
 		dstate_addcmd("shutdown.stayoff");
 	}
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/solis.c b/drivers/solis.c
index 78e83e00a8..3f9a4ac2eb 100644
--- a/drivers/solis.c
+++ b/drivers/solis.c
@@ -1113,13 +1113,15 @@ void upsdrv_makevartable(void)
 	
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B9600);
 
 	ser_set_dtr(upsfd, 1);
 	ser_set_rts(upsfd, 0);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/tripplite.c b/drivers/tripplite.c
index 78ef2539e2..1c7d918cb2 100644
--- a/drivers/tripplite.c
+++ b/drivers/tripplite.c
@@ -568,7 +568,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "rebootdelay", msg);
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B2400);
@@ -579,6 +579,8 @@ void upsdrv_initups(void)
 		startdelay = atoi(getval("startdelay"));
 	if (getval("rebootdelay"))
 		bootdelay = atoi(getval("rebootdelay"));
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/tripplite_usb.c b/drivers/tripplite_usb.c
index 8fa0ef3f8b..6101ed95c7 100644
--- a/drivers/tripplite_usb.c
+++ b/drivers/tripplite_usb.c
@@ -1298,7 +1298,7 @@ void upsdrv_makevartable(void)
  * @todo Allow binding based on firmware version (which seems to vary wildly
  * from unit to unit)
  */
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char *regex_array[6];
 	int r;
@@ -1351,6 +1351,8 @@ void upsdrv_initups(void)
 	if (getval("rebootdelay"))
 		bootdelay = atoi(getval("rebootdelay"));
 #endif
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/tripplitesu.c b/drivers/tripplitesu.c
index d0d0563760..4c81625ddd 100644
--- a/drivers/tripplitesu.c
+++ b/drivers/tripplitesu.c
@@ -845,10 +845,12 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "lowbatt", "Set low battery level, in percent");
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	upsfd = ser_open(device_path);
 	ser_set_speed(upsfd, device_path, B2400);
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
diff --git a/drivers/upscode2.c b/drivers/upscode2.c
index 1a5a6a25fb..3687f454a9 100644
--- a/drivers/upscode2.c
+++ b/drivers/upscode2.c
@@ -460,7 +460,7 @@ void upsdrv_help(void)
 }
 
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	struct termios tio;
 	int baud = B1200;
@@ -529,6 +529,8 @@ void upsdrv_initups(void)
 	upsdebugx(1, "use_crlf = %d", use_crlf);
 	use_pre_lf = testvar("use_pre_lf");
 	upsdebugx(1, "use_pre_lf = %d", use_pre_lf);
+
+	return 1;
 }
 
 
diff --git a/drivers/usbhid-ups.c b/drivers/usbhid-ups.c
index 1de26b42f6..fe1870b312 100644
--- a/drivers/usbhid-ups.c
+++ b/drivers/usbhid-ups.c
@@ -804,6 +804,8 @@ void upsdrv_updateinfo(void)
 	/* Get HID notifications on Interrupt pipe first */
 	if (use_interrupt_pipe == TRUE) {
 		if (comm_driver->claim_interface(udev, 0) != 0) {
+			/* flag for reconnect */
+			hd = NULL;
 			return;
 		}
 
@@ -904,71 +906,86 @@ void upsdrv_initinfo(void)
 	upsh.instcmd = instcmd;
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
+	static int initups_stage = 0;
+
 	int ret;
 	char *val;
+
+	if (initups_stage == 0) {
 #ifdef SHUT_MODE
-	/*!
-	 * SHUT is a serial protocol, so it needs
-	 * only the device path
-	 */
-	upsdebugx(1, "upsdrv_initups...");
+		/*!
+		 * SHUT is a serial protocol, so it needs
+		 * only the device path
+		 */
+		upsdebugx(1, "upsdrv_initups...");
 
-	subdriver_matcher = device_path;
+		subdriver_matcher = device_path;
 #else
-	char *regex_array[6];
+		char *regex_array[6];
 
-	upsdebugx(1, "upsdrv_initups...");
+		upsdebugx(1, "upsdrv_initups...");
 
-	subdriver_matcher = &subdriver_matcher_struct;
+		subdriver_matcher = &subdriver_matcher_struct;
 
-	/* enforce use of the "vendorid" option if "explore" is given */
-	if (testvar("explore") && getval("vendorid")==NULL) {
-		fatalx(EXIT_FAILURE, "must specify \"vendorid\" when using \"explore\"");
-	}
+		/* enforce use of the "vendorid" option if "explore" is given */
+		if (testvar("explore") && getval("vendorid")==NULL) {
+			fatalx(EXIT_FAILURE, "must specify \"vendorid\" when using \"explore\"");
+		}
 
-	/* Activate maxreport tweak */
-	if (testvar("maxreport")) {
-		max_report_size = 1;
-	}
+		/* Activate maxreport tweak */
+		if (testvar("maxreport")) {
+			max_report_size = 1;
+		}
 
-	/* process the UPS selection options */
-	regex_array[0] = getval("vendorid");
-	regex_array[1] = getval("productid");
-	regex_array[2] = getval("vendor");
-	regex_array[3] = getval("product");
-	regex_array[4] = getval("serial");
-	regex_array[5] = getval("bus");
+		/* process the UPS selection options */
+		regex_array[0] = getval("vendorid");
+		regex_array[1] = getval("productid");
+		regex_array[2] = getval("vendor");
+		regex_array[3] = getval("product");
+		regex_array[4] = getval("serial");
+		regex_array[5] = getval("bus");
 
-	ret = USBNewRegexMatcher(&regex_matcher, regex_array, REG_ICASE | REG_EXTENDED);
-	switch(ret)
-	{
-	case 0:
-		break;
-	case -1:
-		fatal_with_errno(EXIT_FAILURE, "HIDNewRegexMatcher()");
-	default:
-		fatalx(EXIT_FAILURE, "invalid regular expression: %s", regex_array[ret]);
-	}
+		ret = USBNewRegexMatcher(&regex_matcher, regex_array, REG_ICASE | REG_EXTENDED);
+		switch(ret)
+		{
+		case 0:
+			break;
+		case -1:
+			fatal_with_errno(EXIT_FAILURE, "HIDNewRegexMatcher()");
+		default:
+			fatalx(EXIT_FAILURE, "invalid regular expression: %s", regex_array[ret]);
+		}
 
-	/* link the matchers */
-	subdriver_matcher->next = regex_matcher;
+		/* link the matchers */
+		subdriver_matcher->next = regex_matcher;
 #endif /* SHUT_MODE */
+		initups_stage = 1;
+	}
 
-	/* Search for the first supported UPS matching the
-	   regular expression (USB) or device_path (SHUT) */
-	ret = comm_driver->open(&udev, &curDevice, subdriver_matcher, &callback, FALSE);
-	if (ret < 1)
-		fatalx(EXIT_FAILURE, "No matching HID UPS found");
+	if (initups_stage == 1) {
+		/* Search for the first supported UPS matching the
+		   regular expression (USB) or device_path (SHUT) */
+		ret = comm_driver->open(&udev, &curDevice, subdriver_matcher, &callback, FALSE);
+		if (ret < 1) {
+			upslogx(LOG_ERR, "No matching HID UPS found");
+			return 0;
+		}
 
-	hd = &curDevice;
+		hd = &curDevice;
 
-	upsdebugx(1, "Detected a UPS: %s/%s", hd->Vendor ? hd->Vendor : "unknown",
-		hd->Product ? hd->Product : "unknown");
+		upsdebugx(1, "Detected a UPS: %s/%s", hd->Vendor ? hd->Vendor : "unknown",
+			hd->Product ? hd->Product : "unknown");
 
+		initups_stage = 2;
+	}
+
+	// after this part there aren't any more things to retry, so stop
+	// tracking the stage
 	if (hid_ups_walk(HU_WALKMODE_INIT) == FALSE) {
-		fatalx(EXIT_FAILURE, "Can't initialize data from HID UPS");
+		upslogx(LOG_ERR, "Can't initialize data from HID UPS");
+		return 0;
 	}
 
 	if (dstate_getinfo("battery.charge.low")) {
@@ -1010,6 +1027,8 @@ void upsdrv_initups(void)
 		dstate_addcmd("shutdown.return");
 		dstate_addcmd("shutdown.stayoff");
 	}
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)
@@ -1185,6 +1204,8 @@ static bool_t hid_ups_walk(walkmode_t mode)
 	int		retcode;
 
 	if (comm_driver->claim_interface(udev, 0) != 0) {
+		/* Uh oh, got to reconnect! */
+		hd = NULL;
 		return FALSE;
 	}
 
diff --git a/drivers/victronups.c b/drivers/victronups.c
index 5b6cf6d406..833b80a461 100644
--- a/drivers/victronups.c
+++ b/drivers/victronups.c
@@ -514,7 +514,7 @@ void upsdrv_makevartable(void)
 	addvar(VAR_VALUE, "modelname", "Seting model name"); 
 }
 
-void upsdrv_initups(void)
+int upsdrv_initups(void)
 {
 	char temp[ LENGTH_TEMP ], *usd = NULL;  /* = NULL je dulezite jen pro prekladac */
 	
@@ -551,6 +551,8 @@ void upsdrv_initups(void)
 	/* the upsh handlers can't be done here, as they get initialized
 	 * shortly after upsdrv_initups returns to main.
 	 */
+
+	return 1;
 }
 
 void upsdrv_cleanup(void)

From d6af1ea05fcfd4383c5c8522edb24fd51e9138d0 Mon Sep 17 00:00:00 2001
From: "Stephen J. Butler" <stephen.butler@gmail.com>
Date: Sat, 19 Apr 2014 15:42:10 -0500
Subject: [PATCH 4/4] Fix linux double-free with usb_close(). Prob caused by
 temporarily assigning *udevp handles to devices we skip and then usb_close().
 Don't assign *udevp till we're sure we're going to return it.

---
 drivers/libusb.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/libusb.c b/drivers/libusb.c
index 955c366997..7f74142b39 100644
--- a/drivers/libusb.c
+++ b/drivers/libusb.c
@@ -148,10 +148,8 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 	usb_find_busses();
 	usb_find_devices();
 
-#ifndef __linux__ /* SUN_LIBUSB (confirmed to work on Solaris and FreeBSD) */
-	/* Causes a double free corruption in linux if device is detached! */
 	libusb_close(*udevp);
-#endif
+	*udevp = NULL;
 
 	for (bus = usb_busses; bus; bus = bus->next) {
 		for (dev = bus->devices; dev; dev = dev->next) {
@@ -163,7 +161,7 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 
 			/* open the device */
 			claimed = 0;
-			*udevp = udev = usb_open(dev);
+			udev = usb_open(dev);
 			if (!udev) {
 				upsdebugx(2, "Failed to open device, skipping. (%s)", usb_strerror());
 				continue;
@@ -233,6 +231,7 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 			upsdebugx(2, "Device matches");
 
 			if (!callback) {
+				*udevp = udev;
 				return 1;
 			}
 
@@ -352,6 +351,7 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 				claimed = 0;
 			}
 
+			*udevp = udev;
 			return rdlen;
 
 		next_device:
@@ -363,7 +363,6 @@ static int libusb_open(usb_dev_handle **udevp, USBDevice_t *curDevice, USBDevice
 		}
 	}
 
-	*udevp = NULL;
 	upsdebugx(2, "No appropriate HID device found");
 	fflush(stdout);