Re: [PATCH 0/7] media: v4l2-subdev: Rename pad config 'try_*' fields

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

On 24/10/2023 09:55, Eugen Hristev wrote:
> On 10/24/23 00:40, Laurent Pinchart wrote:
>> Hello,
> 
> Hello Laurent,
> 
>>
>> This series is the result of me getting bothered by the following note
>> in the documentation of the v4l2_subdev_pad_config structure:
>>
>>   * Note: This struct is also used in active state, and the 'try' 
>> prefix is
>>   * historical and to be removed.
>>
>> So I decided to drop the prefix.
>>
>> Patches 1/7 to 6/7 replace direct usage of the fields in drivers with
>> the corresponding accessor functions. There was a relatively large
>> number of them in sensor drivers (in 6/7), but more worryingly, the
>> atmel-isi (1/7), microchip-isc (2/7) and tegra-video (5/7) should really
>> not have messed up with creating a v4l2_subdev_pad_config structure
>> manually. I urge the maintainers of those drivers to address the issue.
> 
> Could you hint a bit about how the issue should be addressed ?
> Instead of creating a `v4l2_subdev_pad_config`, one should use 
> v4l2_subdev_lock_and_get_active_state() ? Is this the right way to do it ?

I had a quick look at atmel-isi. If I understand it right, it does not 
expose the subdevs to the userspace, and 'isi->entity.subdev' refers to 
the sensor.

In that case I think using v4l2_subdev_call_state_active() and 
v4l2_subdev_call_state_try() should usually work.

If there are cases where the same try state needs to be used for 
multiple calls, then the state management has to be done manually with 
__v4l2_subdev_state_alloc() and __v4l2_subdev_state_free() (e.g. 
drivers/media/platform/renesas/rcar-vin/rcar-v4l2.c).

  Tomi