Re: [PATCH] media: microchip: isc: Initialize DMA lock before requesting IRQ

[Eugen Hristev <ehristev@kernel.org>]

On 9/19/26 04:10, Runyu Xiao wrote:
> Hi Hans and Eugen,
> 
> Thanks for taking a look at this.
> 
> On Sun, 30 Aug 2026, I wrote:
>> The ISC interrupt can run before asynchronous subdevice completion,
>> but the DMA queue lock was initialized from isc_async_complete().
>> Initialize it in each SoC probe before requesting the auto-enabled IRQ.
> 
> On Thu, 10 Sep 2026, Hans Verkuil wrote:
>> It's dubious to just init dma_queue_lock here but not
>> INIT_LIST_HEAD(&isc->dma_queue);
>>
>> I think Eugen needs to look at this as well to see if this is actually
>> a valid issue at all.
>>
>> In any case, this patch doesn't look right to me.
> 
> You're right that moving dma_queue_lock alone is not enough. The interrupt
> handler also accesses dma_queue, comp, and awb_work, which are initialized
> later from isc_async_complete(). I also need to confirm whether an interrupt
> can actually be pending at this point, and whether the required clocks and
> hardware state are ready during probe.
> 
> I have not established that yet, so I'll drop this version for now rather
> than send a v2 that only moves another initialization. Eugen, could you
> please confirm the expected reset and interrupt state during probe? If there
> is a real probe-time path, I'll revisit this with the complete ordering.

Added Balakrishnan , he can test and review your patch.

Eugen>
> Thanks,
> Runyu