RE: [PATCH] usb: dwc3: gadget: don't remove the request if bus-expired

From: Felipe Balbi
Date: Mon Jan 21 2019 - 04:03:48 EST


"Zengtao (B)" <prime.zeng@xxxxxxxxxxxxx> writes:
>>-----Original Message-----
>>From: Felipe Balbi [mailto:felipe.balbi@xxxxxxxxxxxxxxx]
>>Sent: Monday, January 14, 2019 4:13 PM
>>To: Zengtao (B) <prime.zeng@xxxxxxxxxxxxx>
>>Cc: Zengtao (B) <prime.zeng@xxxxxxxxxxxxx>; Greg Kroah-Hartman
>><gregkh@xxxxxxxxxxxxxxxxxxx>; linux-usb@xxxxxxxxxxxxxxx;
>>Subject: Re: [PATCH] usb: dwc3: gadget: don't remove the request if
>>* PGP Signed by an unknown key
>>Zeng Tao <prime.zeng@xxxxxxxxxxxxx> writes:
>>> We have already returned EAGAIN for bus-expiry, and it's designed to
>>> start with a future Frame number and start the transfer again. So we
>>> should not remove the request for that case.
>>> Signed-off-by: Zeng Tao <prime.zeng@xxxxxxxxxxxxx>
>>Do we need a Fixes tag here? How about Cc stable? Can you share
>>tracepoints exposing the problem?
> I am not sure that we need to Fixes tag, it's not related to any single patch, but
> there is definitely something wrong, after rethinking it again, I found that there
> are still some problems for this patch, for the reties inside the driver, we should not
> remove the request, but if we return -EAGAIN to the gadget layer, we should because
> the gadget will requeue the request again if we return -EAGAIN.
> Any suggestions.

Well, that needs to be patched, sure. I'm just saying that we need to
blame a patch that was incomplete so we know which stable releases need
this. Perhaps the patch at fault here was my patch adding the retry
method for isoc transfers.


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