Re: [PATCH v3 1/5] media: mc: add manual request completion

Hans Verkuil
2025-06-09T09:58:05Z

On 09/06/2025 11:42, Sakari Ailus wrote:
> Hi,
>
> On Thu, Jun 05, 2025 at 08:41:45AM -0400, Nicolas Dufresne wrote:
>> Hi Hans, Sakari,
>>
>> Le jeudi 05 juin 2025 à 09:48 +0000, Sakari Ailus a écrit :
>>>> It's not user-triggerable, if this happens, then it is a driver bug.
>>>
>>> If there is a driver bug, it could well be user-triggerable, wouldn't it?
>>> Testing may not uncover all such cases.
>>
>> You are both right, if the driver is not used, the warning will never
>> trigger. I was worried of the hit of a thread safe ONCE implementation,
>> but WARN_ONCE is simply not, it can warn few time before it stops if
>> called from multiple CPUs at the same time. In that specific function,
>> I can move all the checks inside the lock to make it truly once.
>>
>> Now its up to you, I don't have strong preference. These are driver errors,
>> and usually quite critical. They are not bug_on simply because we have a
>> crash free resolution, but its probably not functional anymore.
>
> I'd prefer _ONCE variants, I wonder what Hans thinks.
>

I have no particular preference.

Regards,

Hans