On raspberry pi with VC4 drm graphics driver DRM_IOCTL_WAIT_VBLANK
is failing returning EINVAL for some reason, applying  drmWaitVBlank hack
also on EINVAL until a proper solution is provided.

Signed-off-by: Francesco Pham <francesco.pham@huawei.com>

This simplifies and improves the hack added to libdrm to handle drivers (like
virtio drm) that does not support DRM_IOCTL_WAIT_VBLANK, and tries to return at
60 Hz points in time.

Signed-off-by: Esben Haabendal <esben@geanix.com>

Robert Drab authored 2 years ago and Francesco Pham committed 2 years ago

Signed-off-by: Robert Drab <robert.drab@huawei.com>

Signed-off-by: Robert Drab <robert.drab@huawei.com>