Re: [PATCH v2 03/17] drm/msm/a6xx: Switch to preemption safe AO counter

[Akhil P Oommen]

On 3/27/2026 5:02 PM, Konrad Dybcio wrote:
> On 3/27/26 1:13 AM, Akhil P Oommen wrote:
>> CP_ALWAYS_ON_COUNTER is not save-restored during preemption, so it won't
>> provide accurate data about the 'submit' when preemption is enabled.
>> Switch to CP_ALWAYS_ON_CONTEXT which is preemption safe.
>>
>> Fixes: e7ae83da4a28 ("drm/msm/a6xx: Implement preemption for a7xx targets")
>> Signed-off-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxxxx>
>> ---
> 
> (this is not a blocking comment)
> 
> would the _COUNTER counter be useful to keep for any other purpose?

That is actually a good question. I was fixated on the fdinfo aspect
that I missed that this is used in the submit_retire trace too. In the
trace, I think it is preferable to use the _COUNTER (or keep both) so
that we can visualize the order in which GPU processed the submits.

Rob, what do you think? If required we can drop this patch from this
series. Or I can send a fix up as this affect only the ftrace.

-Akhil.

> 
> Konrad