After thinking about this topic a bit more I've reached the conclusion
that implementing this doesn't make sense:
- The locking is all wrong: set_config(NULL) will also unlink encoders
and connectors, but those links are protected with the mode_config
mutex. In the ->disable_plane callback we only hold all modeset
locks, but eventually we want to switch to just grabbing the
per-crtc (and maybe per-plane) locks as needed, maybe based on
ww_mutexes. Having a callback which absolutely needs all modeset
locks is bad for this conversion.
Note that the same isn't true for the provided ->update_plane since
we've audited the crtc helpers to make sure that not encoder or
connector links are changed.
- There's no way to re-enable the plane with an ->update_plane: The
connectors/encoder links are lost and so we can't re-enable the
CRTC. Even without that issue the driver might have reassigned some
shared resources (as opposed to e.g. DPMS off, where drivers are not
allowed to do that to make sure the CRTC can be enabled again).
- The semantics don't make much sense: Userspace asked to scan out
black (or some other color if the driver supports a background
color), not that the screen be disabled.
- Implementing proper primary plane support (i.e. actually disabling
the primary plane without disabling the CRTC) is really simple, at
least if all the hw needs is flipping a bit. The big task is
auditing all the interactions with other ioctls when the CRTC is on
but there's no primary plane (e.g. pageflips). And some of that work
still needs to be done.
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Add a new drm_crtc_init_with_planes() to allow drivers to provide
specific primary and cursor planes at CRTC initialization. The existing
drm_crtc_init() interface remains to avoid driver churn in existing
drivers; it will initialize the CRTC with a plane helper-created primary
plane and no cursor plane.
v2:
- Move drm_crtc_init() to plane helper file so that nothing in the DRM
core depends on helpers. [suggested by Daniel Vetter]
- Keep cursor parameter to drm_crtc_init_with_planes() a void* until
we actually add cursor support. [suggested by Daniel Vetter]
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
When we expose non-overlay planes to userspace, they will become
accessible via standard userspace plane API's. We should be able to
handle the standard plane operations against primary planes in a generic
way via the modeset handler.
Drivers that can program primary planes more efficiently, that want to
use their own primary plane structure to track additional information,
or that don't have the limitations assumed by the helpers are free to
provide their own implementation of some or all of these handlers.
v3: Tweak kerneldoc formatting slightly to avoid ugliness
v2:
- Move plane helpers to a new file (drm_plane_helper.c)
- Tighten checks on update handler (check for scaling, CRTC coverage,
subpixel positioning)
- Pass proper panning parameters to modeset interface
- Disallow disabling primary plane (and thus CRTC) if other planes are
still active on the CRTC.
- Use a minimal format list that should work on all hardware/drivers.
Drivers may call this function with a more accurate plane list to
enable additional formats they can support.
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
