Re: [PATCH v5 03/10] media: rcar-csi2: Move {enable|disable}_streams() calls

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

Hi,

On 16/06/2026 17:04, Niklas Söderlund wrote:

>>>> rcsi2_irq_thread() also calls rcsi2_stop(), followed by rcsi2_start().
>>>> This is to handle errors reported by the AFIFO_OF, ERRSOTHS and
>>>> ERRSOTSYNCHS interrupts. If the source isn't restarted, such an attempt
>>>> to recover from errors will likely fail. On the other hand, restarting
>>>> the source will likely not lead to great results either.
>>>
>>> Indeed. I think for single-stream use cases the behavior should still be
>>> the same, but for multi-stream use, any enabled stream will keep the
>>> csi2 enabled.
>>>
>>> This kind of error handling sounds a bit fragile. If a restart helps,
>>> don't we need to restart the whole pipeline, not just from csi2-rx
>>> upwards? Or is it guaranteed that the ISP/CS and VIN will continue working?
>>
>> My feeling is that these kind of errors would be best handled in
>> userspace.
> 
> I agree this should be handled in user-space. But since we have (or at
> least did not when this was added) no way to signal to user-space that
> an error have occurred and that action is needed this at least solved
> the error reported by the user.
> 
> If we think this is should be dropped and somehow signal user-space that
> action is needed that is OK for me. But then please remove all of it.
> 
>>
>>> Did this work earlier with the custom VC based routing?
>>
>> That I don't know.
> 
> It did. At least for the only way I had to create the error condition by
> "hot plugging" the CVBS input IIRC.
I think what I could try here is to call v4l2_subdev_disable_streams() 
from rcsi2_irq_thread(), disabling all currently enabled streams from 
the source, and then v4l2_subdev_enable_streams() them back. In theory 
that should do the same as the current code.

I also realized I have a bug here: enable streams does a 
"priv->stream_count += 1", regardless of how many streams the 
source_streams_mask mask contains... I need to check if this same 
pattern is present elsewhere.

  Tomi