Re: .clear_stall

In reply to: Kamal R. Prasad: ".clear_stall"
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From: Hans Petter Selasky <hps_at_selasky.org>
Date: Wed, 13 Apr 2022 09:17:40 UTC

On 4/13/22 08:58, Kamal R. Prasad wrote:
> hello,
> 
>   my xhci driver keeps getting calls from the kernel to the
> .clear_stall interface defined in
> http://fxr.watson.org/fxr/source/dev/usb/controller/xhci.c?im=10#L4365
> 
>   4365         .clear_stall = xhci_ep_clear_stall,
> 
> Can someone tell me why this interface gets called?
> 

Hi Kamal,

This interface gets called typically to reset USB endpoints:

a) before the first endpoint transfer.
b) after an endpoint failure.

This ensures the data toggle value gets synced and no data is lost.

Can you explain what problem you are seeing?

--HPS