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 <st...@rowland.harvard.edu>
---
[as1763]
drivers/hid/usbhid/hid-core.c | 34 +++++++++-------------------------
1 file changed, 9 insertions(+), 25 deletions(-)
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);
}
}
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