Re: [PATCH v2] xhci: pci: Disable soft retry for Renesas uPD720201

[raoxu]

Hi Michal,

Thanks for testing this and for sharing the additional details.

> > > The host reports a transaction error on the RTL8153 interrupt
> > > endpoint, queues a soft reset, and later times out the Stop
> > > Endpoint command while disconnecting the device:
> > >
> > >    Transfer error for slot 8 ep 6 on endpoint
> > >    Soft-reset ep 6, slot 8
> > >    Ignoring reset ep completion code of 1
> > >    xHCI host not responding to stop endpoint command
> > >    xHCI host controller not responding, assume dead
> > >    HC died; cleaning up
>
> There is other stuff too, like concurrent teardown of a separate bulk
> endpoint, not yet sure what exactly breaks these chips.
>
> Would you mind to apply the attached debug patch, reproduce and post
> dmesg from your system for comparison?

Sure. I will apply the debug patch, reproduce the issue next week, and
provide the complete dmesg output for comparison.

> > While debugging this, did xHC controller otherwise seem somewhat
> > functional? Did you for example see port status change events, or
> > transfer events between queuing the stop endpoint command and the
> > timeout?
>
> Mouse continues to work until we kill the HC. And I can even abort the
> command, but then some URB is never given back, so teardown of the USB
> device gets stuck and IDK what would happen later.

I observed the same behavior on my system. During the roughly five
second interval between queuing the Stop Endpoint command and the
command timeout, the USB keyboard and mouse remain fully functional.
They stop working only after the timeout handler marks the host
controller dead and starts the host cleanup.

This suggests that the controller is still processing transfer events
for other endpoints while the Stop Endpoint command is stuck.

Thanks,
Xu Rao