From 8f507ef522d55a6e2f9e11a1c1163a92756da044 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 2 Sep 2014 11:39:15 -0400 Subject: [PATCH] HID: usbhid: improve handling of Clear-Halt and reset This patch changes the way usbhid carries out Clear-Halt and reset. Currently, after a Clear-Halt on the interrupt-IN endpoint, the driver immediately restarts the interrupt URB, even if the Clear-Halt failed. This doesn't work out well when the reason for the failure was that the device was disconnected (when a low- or full-speed device is connected through a hub to an EHCI controller, transfer errors caused by disconnection are reported as stalls by the hub). Instead now the driver will attempt a reset after a failed Clear-Halt. The way resets are carried out is also changed. Now the driver will call usb_queue_reset_device() instead of calling usb_reset_device() directly. This avoids a deadlock that would arise when a device is unplugged: The hid_reset() routine runs as a workqueue item, a reset attempt after the device has been unplugged will fail, failure will cause usbhid to be unbound, and the disconnect routine will try to do cancel_work_sync(). The usb_queue_reset_device() implementation is carefully written to handle scenarios like this one properly. Signed-off-by: Alan Stern Signed-off-by: Jiri Kosina --- drivers/hid/usbhid/hid-core.c | 34 +++++++++------------------------- 1 file changed, 9 insertions(+), 25 deletions(-) diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c index 79cf503..80c5076 100644 --- a/drivers/hid/usbhid/hid-core.c +++ b/drivers/hid/usbhid/hid-core.c @@ -116,40 +116,24 @@ static void hid_reset(struct work_struct *work) 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); } } -- 2.7.4