| Message ID | 20240520134108.net-next.1.Ibeda5c0772812ce18953150da5a0888d2d875150@changeid (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [net-next,1/2] r8152: If inaccessible at resume time, issue a reset | expand |
On Mon, 2024-05-20 at 13:41 -0700, Douglas Anderson wrote: > If we happened to get a USB transfer error during the transition to > suspend then the usb_queue_reset_device() that r8152_control_msg() > calls will get dropped on the floor. This is because > usb_lock_device_for_reset() (which usb_queue_reset_device() uses) > silently fails if it's called when a device is suspended or if too > much time passes. > > Let's resolve this by resetting the device ourselves in r8152's > resume() function. > > NOTE: due to timing, it's _possible_ that we could end up with two USB > resets: the one queued previously and the one called from the resume() > patch. This didn't happen in test cases I ran, though it's conceivably > possible. We can't easily know if this happened since > usb_queue_reset_device() can just silently drop the reset request. In > any case, it's not expected that this is a problem since the two > resets can't run at the same time (because of the device lock) and it > should be OK to reset the device twice. If somehow the double-reset > causes problems we could prevent resets from being queued up while > suspend is running. > > Signed-off-by: Douglas Anderson <dianders@chromium.org> ## Form letter - net-next-closed The merge window for v6.10 has begun and we have already posted our pull request. Therefore net-next is closed for new drivers, features, code refactoring and optimizations. We are currently accepting bug fixes only. Please repost when net-next reopens after May 26th. RFC patches sent for review only are obviously welcome at any time. See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#development-cycle
diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c index 19df1cd9f072..6a3f4b2114ee 100644 --- a/drivers/net/usb/r8152.c +++ b/drivers/net/usb/r8152.c @@ -8554,6 +8554,19 @@ static int rtl8152_system_resume(struct r8152 *tp) usb_submit_urb(tp->intr_urb, GFP_NOIO); } + /* If the device is RTL8152_INACCESSIBLE here then we should do a + * reset. This is important because the usb_lock_device_for_reset() + * that happens as a result of usb_queue_reset_device() will silently + * fail if the device was suspended or if too much time passed. + * + * NOTE: The device is locked here so we can directly do the reset. + * We don't need usb_lock_device_for_reset() because that's just a + * wrapper over device_lock() and device_resume() (which calls us) + * does that for us. + */ + if (test_bit(RTL8152_INACCESSIBLE, &tp->flags)) + usb_reset_device(tp->udev); + return 0; }
If we happened to get a USB transfer error during the transition to suspend then the usb_queue_reset_device() that r8152_control_msg() calls will get dropped on the floor. This is because usb_lock_device_for_reset() (which usb_queue_reset_device() uses) silently fails if it's called when a device is suspended or if too much time passes. Let's resolve this by resetting the device ourselves in r8152's resume() function. NOTE: due to timing, it's _possible_ that we could end up with two USB resets: the one queued previously and the one called from the resume() patch. This didn't happen in test cases I ran, though it's conceivably possible. We can't easily know if this happened since usb_queue_reset_device() can just silently drop the reset request. In any case, it's not expected that this is a problem since the two resets can't run at the same time (because of the device lock) and it should be OK to reset the device twice. If somehow the double-reset causes problems we could prevent resets from being queued up while suspend is running. Signed-off-by: Douglas Anderson <dianders@chromium.org> --- drivers/net/usb/r8152.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)