A drm_output needs a CRTC only when it is in use. Allocating a CRTC on
creation of drm_output will reserve the CRTC regardless of whether the
output is actually used or not. This may cause creating other
drm_outputs to fail if there are not enough CRTCs.
Instead, allocate the CRTC on drm_output enable() time. A drm_output
will have a valid CRTC only while it is enabled.
This allows us to create drm_output objects arbitrarily and without a
head assignment, which is required by the head-based output API for the
backends. The assigned heads will be known only at enable() time.
Now drm_output_enable() has to call drmModeGetResources() to be able to
find a suitable CRTC. We might want to cache the resources somewhere,
but that is it topic for another patch.
v4: Force resetting unused CRTCs on fini.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Acked-by: Derek Foreman <derekf@osg.samsung.com>
Pekka Paalanen
663d5e9b12