On Mon, Sep 27, 2021 at 8:43 PM Stefan Agner <ste...@agner.ch> wrote: > > There are devices which cause a USB stall when trying to read strings. > Specifically Arduino Mega R3 stalls when trying to read the product > string. > > The stall currently remains unhandled, and subsequent retries submit new > transfers on a stopped endpoint which ultimately cause a crash in > abort_td(): > WARN halted endpoint, queueing URB anyway. > XHCI control transfer timed out, aborting... > Unexpected XHCI event TRB, skipping... (3affe040 00000000 13000000 02008401) > BUG at drivers/usb/host/xhci-ring.c:505/abort_td()! > BUG! > resetting ... > > Linux seems to be able to recover from the stall by issuing a > TRB_RESET_EP command. > > Introduce reset_ep() which issues a TRB_RESET_EP followed by setting the > transfer ring dequeue pointer via TRB_SET_DEQ. This allows to properly > recover from a USB stall error and continue communicating with the USB > device. > > Signed-off-by: Stefan Agner <ste...@agner.ch> > --- > This has been reported on the ML by Mike Hoogstraten a while ago: > https://www.mail-archive.com/u-boot@lists.denx.de/msg390604.html > > FWIW, for the Arduino Mega R3 I also opened an issue: > https://github.com/arduino/ArduinoCore-avr/issues/431 > > -- > Stefan > > drivers/usb/host/xhci-ring.c | 31 +++++++++++++++++++++++++++++++ > 1 file changed, 31 insertions(+) >
Sorry for the delay! Reviewed-by: Bin Meng <bmeng...@gmail.com>
