User-space expects to be able to pick a primary plane for each CRTC exposed by the driver. Make sure this assumption holds in drm_mode_config_validate.
Use the legacy drm_crtc.primary field to check this, because it's simpler and we require drivers to set it anyways. Accumulate a set of primary planes which are already used for a CRTC in a bitmask. Error out if a primary plane is re-used.
v2: new patch
v3: - Use u64 instead of __u64 (Jani) - Use `unsigned int` instead of `unsigned` (Jani)
v4: - Use u32 instead of u64 for plane mask (Ville) - Use drm_plane_mask instead of BIT (Ville) - Fix typos (Ville)
Signed-off-by: Simon Ser contact@emersion.fr Reviewed-by: Daniel Vetter daniel@ffwll.ch Cc: Pekka Paalanen ppaalanen@gmail.com Cc: Jani Nikula jani.nikula@linux.intel.com Cc: Ville Syrjala ville.syrjala@linux.intel.com --- drivers/gpu/drm/drm_mode_config.c | 21 +++++++++++++++++++++ drivers/gpu/drm/drm_plane.c | 6 ++++++ 2 files changed, 27 insertions(+)
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c index 1e5da83fd2a8..7ffc0d6a8e2c 100644 --- a/drivers/gpu/drm/drm_mode_config.c +++ b/drivers/gpu/drm/drm_mode_config.c @@ -626,6 +626,9 @@ void drm_mode_config_validate(struct drm_device *dev) { struct drm_encoder *encoder; struct drm_crtc *crtc; + struct drm_plane *plane; + u32 primary_with_crtc = 0, cursor_with_crtc = 0; + unsigned int num_primary = 0;
if (!drm_core_check_feature(dev, DRIVER_MODESET)) return; @@ -647,12 +650,30 @@ void drm_mode_config_validate(struct drm_device *dev) "Bogus primary plane possible_crtcs: [PLANE:%d:%s] must be compatible with [CRTC:%d:%s]\n", crtc->primary->base.id, crtc->primary->name, crtc->base.id, crtc->name); + WARN(primary_with_crtc & drm_plane_mask(crtc->primary), + "Primary plane [PLANE:%d:%s] used for multiple CRTCs", + crtc->primary->base.id, crtc->primary->name); + primary_with_crtc |= drm_plane_mask(crtc->primary); } if (crtc->cursor) { WARN(!(crtc->cursor->possible_crtcs & drm_crtc_mask(crtc)), "Bogus cursor plane possible_crtcs: [PLANE:%d:%s] must be compatible with [CRTC:%d:%s]\n", crtc->cursor->base.id, crtc->cursor->name, crtc->base.id, crtc->name); + WARN(cursor_with_crtc & drm_plane_mask(crtc->cursor), + "Cursor plane [PLANE:%d:%s] used for multiple CRTCs", + crtc->cursor->base.id, crtc->cursor->name); + cursor_with_crtc |= drm_plane_mask(crtc->cursor); } } + + drm_for_each_plane(plane, dev) { + if (plane->type == DRM_PLANE_TYPE_PRIMARY) { + num_primary++; + } + } + + WARN(num_primary != dev->mode_config.num_crtc, + "Must have as many primary planes as there are CRTCs, but have %u primary planes and %u CRTCs", + num_primary, dev->mode_config.num_crtc); } diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index 49b0a8b9ac02..a1f4510efa83 100644 --- a/drivers/gpu/drm/drm_plane.c +++ b/drivers/gpu/drm/drm_plane.c @@ -54,6 +54,12 @@ * enum drm_plane_type). A plane can be compatible with multiple CRTCs, see * &drm_plane.possible_crtcs. * + * Each CRTC must have a unique primary plane userspace can attach to enable + * the CRTC. In other words, userspace must be able to attach a different + * primary plane to each CRTC at the same time. Primary planes can still be + * compatible with multiple CRTCs. There must be exactly as many primary planes + * as there are CRTCs. + * * Legacy uAPI doesn't expose the primary and cursor planes directly. DRM core * relies on the driver to set the primary and optionally the cursor plane used * for legacy IOCTLs. This is done by calling drm_crtc_init_with_planes(). All