xhci: Don't clear hub TT buffer on ep0 protocol stall
authorMathias Nyman <mathias.nyman@linux.intel.com>
Tue, 21 Apr 2020 14:08:22 +0000 (17:08 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 29 Apr 2020 14:33:23 +0000 (16:33 +0200)
commitfceab238c534eca02253c01f3bd5db391acd47b0
treee4175f8c138cd973b2c63477784ecbb95e7672d6
parent54470b0bd16aabc05c1d5fe2037e7fadf7869c16
xhci: Don't clear hub TT buffer on ep0 protocol stall

commit 8f97250c21f0cf36434bf5b7ddf4377406534cd1 upstream.

The default control endpoint ep0 can return a STALL indicating the
device does not support the control transfer requests. This is called
a protocol stall and does not halt the endpoint.

xHC behaves a bit different. Its internal endpoint state will always
be halted on any stall, even if the device side of the endpiont is not
halted. So we do need to issue the reset endpoint command to clear the
xHC host intenal endpoint halt state, but should not request the HS hub
to clear the TT buffer unless device side of endpoint is halted.

Clearing the hub TT buffer at protocol stall caused ep0 to become
unresponsive for some FS/LS devices behind HS hubs, and class drivers
failed to set the interface due to timeout:

usb 1-2.1: 1:1: usb_set_interface failed (-110)

Fixes: ef513be0a905 ("usb: xhci: Add Clear_TT_Buffer")
Cc: <stable@vger.kernel.org> # v5.3
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200421140822.28233-4-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/host/xhci-ring.c