drm/i915: Unconditionally clear plane visibility, v2.

We need to assume the plane has been visible before, even if no CRTC
is assigned to the plane. This is because when enabling a nv12 plane
on gen11, we will have to enable an extra plane and make it visible
by marking it in crtc_state->active_planes for
intel_update_planes_on_crtc().

Additionally, clear visible flag in intel_plane_atomic_check, in case
we ever hit a bug with visibility. Our code implicitly assumes that
plane_state->visible is only true when crtc and fb are set,
so we will either null deref in intel_fbc_choose_crtc() or
do something bad during the actual commit which cares even more.

Changes since v1:
- Unconditionally clear crtc_state->active_planes as well.
- Reword commit message, since this is now a preparation patch for
  NV12 Y / UV plane linking.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[mlankhorst: Clear nv12_planes in the beginning as well, clarify commit message]
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180920102711.4184-4-maarten.lankhorst@linux.intel.com

diff --git a/drivers/gpu/drm/i915/intel_atomic_plane.c b/drivers/gpu/drm/i915/intel_atomic_plane.c
index aabebe0..59f6ab6 100644 (file)
--- a/drivers/gpu/drm/i915/intel_atomic_plane.c
+++ b/drivers/gpu/drm/i915/intel_atomic_plane.c
@@ -117,10 +117,14 @@ int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_
        struct intel_plane *intel_plane = to_intel_plane(plane);
        int ret;
 
+       crtc_state->active_planes &= ~BIT(intel_plane->id);
+       crtc_state->nv12_planes &= ~BIT(intel_plane->id);
+       intel_state->base.visible = false;
+
+       /* If this is a cursor plane, no further checks are needed. */
        if (!intel_state->base.crtc && !old_plane_state->base.crtc)
                return 0;
 
-       intel_state->base.visible = false;
        ret = intel_plane->check_plane(crtc_state, intel_state);
        if (ret)
                return ret;
@@ -128,13 +132,9 @@ int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_
        /* FIXME pre-g4x don't work like this */
        if (state->visible)
                crtc_state->active_planes |= BIT(intel_plane->id);
-       else
-               crtc_state->active_planes &= ~BIT(intel_plane->id);
 
        if (state->visible && state->fb->format->format == DRM_FORMAT_NV12)
                crtc_state->nv12_planes |= BIT(intel_plane->id);
-       else
-               crtc_state->nv12_planes &= ~BIT(intel_plane->id);
 
        return intel_plane_atomic_calc_changes(old_crtc_state,
                                               &crtc_state->base,
@@ -152,6 +152,7 @@ static int intel_plane_atomic_check(struct drm_plane *plane,
        const struct drm_crtc_state *old_crtc_state;
        struct drm_crtc_state *new_crtc_state;
 
+       new_plane_state->visible = false;
        if (!crtc)
                return 0;