[FFmpeg-devel] [PATCH 2/2] avutil/hwcontext_vaapi: return ENOSYS for unsupported operation

[Mark Thompson]

On 27/10/2023 16:37, Zhao Zhili wrote:
> From: Zhao Zhili <zhilizhao at tencent.com>
> 
> av_hwframe_transfer_data try with src_ctx first. If the operation
> failed with AVERROR(ENOSYS), it will try again with dst_ctx. Return
> AVERROR(EINVAL) makes the second step being skipped.
> ---
>   libavutil/hwcontext_vaapi.c | 10 +++++-----
>   1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/libavutil/hwcontext_vaapi.c b/libavutil/hwcontext_vaapi.c
> index 558fed94c6..bb28bcf588 100644
> --- a/libavutil/hwcontext_vaapi.c
> +++ b/libavutil/hwcontext_vaapi.c
> @@ -217,7 +217,7 @@ static int vaapi_get_image_format(AVHWDeviceContext *hwdev,
>               return 0;
>           }
>       }
> -    return AVERROR(EINVAL);
> +    return AVERROR(ENOSYS);
>   }
>   
>   static int vaapi_frames_get_constraints(AVHWDeviceContext *hwdev,
> @@ -805,19 +805,19 @@ static int vaapi_map_frame(AVHWFramesContext *hwfc,
>   
>       if (!ctx->derive_works && (flags & AV_HWFRAME_MAP_DIRECT)) {
>           // Requested direct mapping but it is not possible.
> -        return AVERROR(EINVAL);
> +        return AVERROR(ENOSYS);
>       }
>       if (dst->format == AV_PIX_FMT_NONE)
>           dst->format = hwfc->sw_format;
>       if (dst->format != hwfc->sw_format && (flags & AV_HWFRAME_MAP_DIRECT)) {
>           // Requested direct mapping but the formats do not match.
> -        return AVERROR(EINVAL);
> +        return AVERROR(ENOSYS);

This one seems wrong?  The user requested that (say) a YUV surface is directly mapped to an RGB frame.  That's an invalid request from the user, not an unsupported feature.

If you're changing the return values then this test and the previous one probably want to therefore be in the opposite order as well.

>       }
>   
>       err = vaapi_get_image_format(hwfc->device_ctx, dst->format, &image_format);
>       if (err < 0) {
>           // Requested format is not a valid output format.
> -        return AVERROR(EINVAL);
> +        return err;
>       }
>   
>       map = av_malloc(sizeof(*map));
> @@ -992,7 +992,7 @@ static int vaapi_map_to_memory(AVHWFramesContext *hwfc, AVFrame *dst,
>       if (dst->format != AV_PIX_FMT_NONE) {
>           err = vaapi_get_image_format(hwfc->device_ctx, dst->format, NULL);
>           if (err < 0)
> -            return AVERROR(ENOSYS);
> +            return err;
>       }
>   
>       err = vaapi_map_frame(hwfc, dst, src, flags);

- Mark