[PATCH weston 3/4] simple-dmabuf-drm: use GBM generic calls

[Daniel Stone]

Hi Emilio,

On Wed, 11 Jul 2018 at 12:53, Emilio Pozuelo Monfort <pochu27 at gmail.com> wrote:
> As for NV12 support: I tried to make gbm support that in
> backends/dri/gbm_dri.c by adding a mapping to gbm_dri_visuals_table
> from GBM_FORMAT_NV12 to __DRI_IMAGE_FOURCC_NV12 or DRM_FORMAT_NV12,
> but that didn't work. I'm not sure what we can do here. Does anybody
> who know the stack better have any pointers?

There is no native NV12 support, apart form some special-case handling
when using them as textures. For NV12, you would want to create two
separate BOs - one with GBM_FORMAT_R8 (luma/Y), and one with
GBM_FORMAT_RG88 (chroma/UV), and fill those like you would fill the
two planes of a native NV12 surface. They can then be combined and
sent to the compositor as two planes of a single NV12 image.

Cheers,
Daniel