I recently posted (but did not submit) a more comprehensive solution to
this and other related problems.  For example, HID devices typically
run at low speed or full speed.  When attached through a hub to an EHCI
controller (very common on modern systems), unplugging the device
causes -EPIPE errors, so the driver calls usb_clear_halt and restarts
the interrupt pipe.  Of course, the same failure occurs again, so
there's a lengthy flurry of useless error messages.

This patch changes the driver so that after usb_clear_halt fails, it
will try to do a port reset.  And if that fails, the driver will be
unbound from the device.  This avoids infinite loops.

What do you think?

Alan Stern



Index: usb-3.16/drivers/hid/usbhid/hid-core.c
===================================================================

--- usb-3.16.orig/drivers/hid/usbhid/hid-core.c
+++ usb-3.16/drivers/hid/usbhid/hid-core.c

@@ -116,40 +116,24 @@ static void hid_reset(struct work_struct
        struct usbhid_device *usbhid =
                container_of(work, struct usbhid_device, reset_work);
        struct hid_device *hid = usbhid->hid;
-       int rc = 0;
+       int rc;

        if (test_bit(HID_CLEAR_HALT, &usbhid->iofl)) {
                dev_dbg(&usbhid->intf->dev, "clear halt\n");
                rc = usb_clear_halt(hid_to_usb_dev(hid), usbhid->urbin->pipe);
                clear_bit(HID_CLEAR_HALT, &usbhid->iofl);
-               hid_start_in(hid);
-       }
-
-       else if (test_bit(HID_RESET_PENDING, &usbhid->iofl)) {
-               dev_dbg(&usbhid->intf->dev, "resetting device\n");
-               rc = usb_lock_device_for_reset(hid_to_usb_dev(hid), usbhid->intf);
                if (rc == 0) {
-                       rc = usb_reset_device(hid_to_usb_dev(hid));
-                       usb_unlock_device(hid_to_usb_dev(hid));
+                       hid_start_in(hid);
+               } else {
+                       dev_dbg(&usbhid->intf->dev,
+                                       "clear-halt failed: %d\n", rc);
+                       set_bit(HID_RESET_PENDING, &usbhid->iofl);
                }
-               clear_bit(HID_RESET_PENDING, &usbhid->iofl);
        }

-       switch (rc) {
-       case 0:
-               if (!test_bit(HID_IN_RUNNING, &usbhid->iofl))
-                       hid_io_error(hid);
-               break;
-       default:
-               hid_err(hid, "can't reset device, %s-%s/input%d, status %d\n",
-                       hid_to_usb_dev(hid)->bus->bus_name,
-                       hid_to_usb_dev(hid)->devpath,
-                       usbhid->ifnum, rc);
-               /* FALLTHROUGH */
-       case -EHOSTUNREACH:
-       case -ENODEV:
-       case -EINTR:
-               break;
+       if (test_bit(HID_RESET_PENDING, &usbhid->iofl)) {
+               dev_dbg(&usbhid->intf->dev, "resetting device\n");
+               usb_queue_reset_device(usbhid->intf);
        }
 }