Clear USB fault when getting device ID (Issue #1606)

Author: michaelrsweet

CHANGES.md

@@ -11,6 +11,7 @@ Changes in CUPS v2.4.20 (YYYY-MM-DD)
   mode.
 - Increased the size of the SNMP supply name buffer used by the network backends
   (Issue #1604)
+- The USB backend now clears a halt on USB errors (Issue #1606)
 - Fixed mapping of standard PPD/PWG/legacy media size names to the local PPD
   size name (Issue #1375)
 - Fixed handling of multiple PPD: keywords from filters (Issue #1562,

backend/usb-libusb.c

@@ -1,7 +1,7 @@
 /*
  * LIBUSB interface code for CUPS.
  *
- * Copyright © 2020-2025 by OpenPrinting.
+ * Copyright © 2020-2026 by OpenPrinting.
  * Copyright © 2007-2019 by Apple Inc.
  *
  * Licensed under Apache License v2.0.  See the file "LICENSE" for more
@@ -1075,16 +1075,15 @@ get_device_id(usb_printer_t *printer,	/* I - Printer */
               char          *buffer,	/* I - String buffer */
               size_t        bufsize)	/* I - Number of bytes in buffer */
 {
-  size_t	length;				/* Length of device ID */
+  int		err;			/* libusb error */
+  size_t	length;			/* Length of device ID */
 
 
-  if (libusb_control_transfer(printer->handle,
-			      LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_ENDPOINT_IN |
-			      LIBUSB_RECIPIENT_INTERFACE,
-			      0, printer->conf,
-			      (printer->iface << 8) | printer->altset,
-			      (unsigned char *)buffer, bufsize, 5000) < 0)
+  if ((err = libusb_control_transfer(printer->handle, LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_ENDPOINT_IN | LIBUSB_RECIPIENT_INTERFACE, 0, printer->conf, (printer->iface << 8) | printer->altset, (unsigned char *)buffer, bufsize, 5000)) < 0)
   {
+    if (err == LIBUSB_ERROR_PIPE)
+      libusb_clear_halt(printer->handle, printer->read_endp);
+
     *buffer = '\0';
     return (-1);
   }