On 06/08/2020 05:18, Laurent Pinchart wrote:
> The BO pitches are unconditionally set to the frame buffer pitch, for
> all planes. This is correct for semiplanar YUV formats, as they
> subsample chroma horizontally by two but combined U and V in a single
> plane, cancelling each other. For fully planar YUV formats, however, the
> horizontal subsampling need to be taken into account to compute the
> pitch. Fix it.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> kms++/src/dumbframebuffer.cpp | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/kms++/src/dumbframebuffer.cpp b/kms++/src/dumbframebuffer.cpp
> index 18f3f152943d..4c3c03164a90 100644
> --- a/kms++/src/dumbframebuffer.cpp
> +++ b/kms++/src/dumbframebuffer.cpp
> @@ -42,6 +42,14 @@ DumbFramebuffer::DumbFramebuffer(Card& card, uint32_t width, uint32_t height, Pi
> struct drm_mode_create_dumb creq = drm_mode_create_dumb();
> creq.width = width;
> creq.height = height / pi.ysub;
> + /*
> + * For fully planar YUV buffers, the chroma planes don't combine
> + * U and V components, their width must thus be divided by the
> + * horizontal subsampling factor.
> + */
> + if (format_info.type == PixelColorType::YUV &&
> + format_info.num_planes == 3)
> + creq.width /= pi.xsub;
This feels a bit of a hack... I think we should somehow have the relevant information in the
PixelFormatInfo. Having the same plane info, { 8, 2, 2 }, for both NV12 UV plane and YUV420 U and V
planes doesn't sound correct.
Should NV12's UV plane be { 16, 2, 2 }? Subsampled formats are confusing... =)
Tomi
--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
