Re: [PATCH v5 17/24] v4l: Add stream to frame descriptor

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

On 18/04/2021 22:27, Laurent Pinchart wrote:
> Hi Tomi and Sakari,
> 
> Thank you for the patch.
> 
> On Thu, Apr 15, 2021 at 04:04:43PM +0300, Tomi Valkeinen wrote:
>> From: Sakari Ailus <sakari.ailus@linux.intel.com>
>>
>> The stream field identifies the stream this frame descriptor applies to in
>> routing configuration across a multiplexed link.
>>
>> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
>> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
>> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
>> ---
>>   include/media/v4l2-subdev.h | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
>> index 30ec011d31e3..436d0445aafd 100644
>> --- a/include/media/v4l2-subdev.h
>> +++ b/include/media/v4l2-subdev.h
>> @@ -338,6 +338,7 @@ enum v4l2_mbus_frame_desc_flags {
>>    * struct v4l2_mbus_frame_desc_entry - media bus frame description structure
>>    *
>>    * @flags:	bitmask flags, as defined by &enum v4l2_mbus_frame_desc_flags.
>> + * @stream:	stream in routing configuration
>>    * @pixelcode:	media bus pixel code, valid if @flags
>>    *		%FRAME_DESC_FL_BLOB is not set.
>>    * @length:	number of octets per frame, valid if @flags
>> @@ -347,6 +348,7 @@ enum v4l2_mbus_frame_desc_flags {
>>    */
>>   struct v4l2_mbus_frame_desc_entry {
>>   	enum v4l2_mbus_frame_desc_flags flags;
>> +	u32 stream;
> 
> As this isn't used in this series, I can't really tell how it will be
> used, so it's hard to review the patch. Should we postpone it to the
> next patch series ?

It's not used here, but it is needed allow the drivers use the features 
introduced in this series. It is used to match routes to frame_descs.

Its usage is quite simple: e.g. when a driver has a route 
(v4l2_subdev_route), it can get the frame_descs from the entity behind 
v4l2_subdev_route.source_pad, and then find the matching frame_desc by 
searching for

v4l2_subdev_route.source_stream == v4l2_mbus_frame_desc_entry.stream

  Tomi