Sjoerd Simons authored Nov 09, 2018 and Nicolas Dufresne committed Nov 11, 2018

When importing an egl image from dmabuf gst_gl_format_from_video_info
was used to work what the result GL format will be. Unfortunately that
will only work if the conventional format and the choosen DRM fourcc for
the format match up.

On etnaviv platforms there is no support for GL_EXT_texture_rg, so the
GL format chosen for YUY2 ends up being GST_GL_LUMINANCE_ALPHA. However
DRM does not do luminance + alpha as it's a legacy GL thing, so the
dmabuf import ends up using DRM_FORMAT_GR88.

To fix this, tie the DRM_FORMAT and the GL format together so they
always match up.