Re: [PATCH v2] usb: xhci: quirk for data loss in ISOC transfers

["Rangoju, Raju" <raju.rangoju@amd.com>]

On 11/13/2024 11:35 AM, Greg KH wrote:
> On Tue, Nov 12, 2024 at 07:02:40PM +0530, Rangoju, Raju wrote:
>>
>>
>> On 11/12/2024 5:54 PM, Greg KH wrote:
>>> On Tue, Nov 12, 2024 at 05:51:04PM +0530, Raju Rangoju wrote:
>>>> During the High-Speed Isochronous Audio transfers, xHCI
>>>> controller on certain AMD platforms experiences momentary data
>>>> loss. This results in Missed Service Errors (MSE) being
>>>> generated by the xHCI.
>>>>
>>>> The root cause of the MSE is attributed to the ISOC OUT endpoint
>>>> being omitted from scheduling. This can happen either when an IN
>>>> endpoint with a 64ms service interval is pre-scheduled prior to
>>>> the ISOC OUT endpoint or when the interval of the ISOC OUT
>>>> endpoint is shorter than that of the IN endpoint. Consequently,
>>>> the OUT service is neglected when an IN endpoint with a service
>>>> interval exceeding 32ms is scheduled concurrently (every 64ms in
>>>> this scenario).
>>>>
>>>> This issue is particularly seen on certain older AMD platforms.
>>>> To mitigate this problem, it is recommended to adjust the service
>>>> interval of the IN endpoint to not exceed 32ms (interval 8). This
>>>> adjustment ensures that the OUT endpoint will not be bypassed,
>>>> even if a smaller interval value is utilized.
>>>>
>>>> Signed-off-by: Raju Rangoju <Raju.Rangoju@amd.com>
>>>
>>> You don't want this backported to any older kernels?  Why not?
>>
>> Hi Greg, Yes, backporting is needed, but some of products were released back
>> in 2018, not sure of the exact commit id to quote here for backporting as
>> there were no precise commits that added this initial support in the first
>> place.
>>
>> Would you mind tagging it to all stable kernels. Let me know if the patch
>> needs to be respinned.
> 
> Yes, please resend it with the proper tag, don't ask maintainers to
> hand-edit changes for you, that does not scale at all.
>

Sure, I'll re-spin with a stable tag.

> thanks,
> 
> greg k-h