Re: [PATCH v2] media: amphion: Add V4L2_FMT_FLAG_DYN_RESOLUTION for VC1L

[Frank Li <Frank.li@oss.nxp.com>]

On Tue, Sep 29, 2026 at 04:30:28PM +0900, Ming Qian wrote:
> The amphion VPU decoder always emits an initial V4L2_EVENT_SOURCE_CHANGE
> event after parsing the resolution from the stream header for VC1 Annex
> L format. Without V4L2_FMT_FLAG_DYN_RESOLUTION, userspace (e.g.
> GStreamer) cannot determine that the driver will signal the initial
> resolution, causing it to skip waiting for the event and fail to set up
> the CAPTURE queue properly.
>
> Add V4L2_FMT_FLAG_DYN_RESOLUTION to the VC1 Annex L format entry to
> indicate that the decoder will emit the source change event during
> initialization, consistent with other coded formats supported by this
> driver.
>
> Fixes: e670f5d672ef ("media: amphion: only insert the first sequence startcode for vc1l format")
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>

Reviewed-by: Frank Li <Frank.Li@nxp.com>

> ---
> Changes in v2:
> - Drop the documentation patch. Nicolas pointed out that
>   V4L2_FMT_FLAG_DYN_RESOLUTION postdates the stateful decoder spec, so any
>   driver setting it is already required to follow that spec. The
>   non-compliant drivers (coda, s5p-mfc) are pre-spec history and not worth
>   bending the spec text around.
> - Drop the RFC prefix, as requested by Nicolas.
> - Link to v1: https://patch.msgid.link/20260608-flag-dyn-resolution-v1-0-44dc65516148@oss.nxp.com
> ---
>  drivers/media/platform/amphion/vdec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/amphion/vdec.c b/drivers/media/platform/amphion/vdec.c
> index a9f0521f2e1a..75808482d090 100644
> --- a/drivers/media/platform/amphion/vdec.c
> +++ b/drivers/media/platform/amphion/vdec.c
> @@ -136,7 +136,7 @@ static const struct vpu_format vdec_formats[] = {
>  		.mem_planes = 1,
>  		.comp_planes = 1,
>  		.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE,
> -		.flags = V4L2_FMT_FLAG_COMPRESSED
> +		.flags = V4L2_FMT_FLAG_DYN_RESOLUTION | V4L2_FMT_FLAG_COMPRESSED
>  	},
>  	{
>  		.pixfmt = V4L2_PIX_FMT_MPEG2,
>
> ---
> base-commit: 2dcdfb625c3b8fe87454e19dfbc54b3e3f0ad70e
> change-id: 20260608-flag-dyn-resolution-f39fd24a0ba2
>
>