etnaviv: fbdev kms and eglfs issue

[Lucas Stach]

Hi Christoph,

Am Freitag, den 12.01.2018, 12:09 +0100 schrieb Christoph Fritz:
> Hi,
> 
>  while using CONFIG_DRM_ETNAVIV in conjunction with
> CONFIG_DRM_FBDEV_EMULATION eglfs programs like qt5-opengles2-test can
> fail to display any content so that the screen just stays black.
> 
> To get to this point, gstreamer with kms sink has to be executed
> before:
> 
>  1. boot system
>  2. $ qt5-opengles2-test
>     -> works and displays fine
>  3. $ gst-launch-1.0 filesrc location=/home/test.webm ! decodebin ! \
>       videoconvert ! kmssink connector-id=41 name=imx-drm sync=0
>     -> works and displays fine

This is a wild guess, but maybe the overlay plane used by kmssink isn't
getting disabled properly when fbdev emulation takes over the display
again.

Regards,
Lucas

>  4. $ qt5-opengles2-test
>     -> FAILS to display any content (but starts and runs fine)
> 
> Is this a known issue?
> 
> Disabling CONFIG_DRM_FBDEV_EMULATION bypasses this issue.
> 
> Any ideas?
> 
> Thanks
>   -- Christoph
>