Commit bfa71b7a authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Joonas Lahtinen
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drm/i915: Unlink NV12 planes earlier 



unlink_nv12_plane() will clobber parts of the plane state
potentially already set up by plane_atomic_check(), so we
must make sure not to call the two in the wrong order.
The problem happens when a plane previously selected as
a Y plane is now configured as a normal plane by user space.
plane_atomic_check() will first compute the proper plane
state based on the userspace request, and unlink_nv12_plane()
later clears some of the state.

This used to work on account of unlink_nv12_plane() skipping
the state clearing based on the plane visibility. But I removed
that check, thinking it was an impossible situation. Now when
that situation happens unlink_nv12_plane() will just WARN
and proceed to clobber the state.

Rather than reverting to the old way of doing things, I think
it's more clear if we unlink the NV12 planes before we even
compute the new plane state.

Cc: stable@vger.kernel.org
Reported-by: default avatarKhaled Almahallawy <khaled.almahallawy@intel.com>
Closes: https://lore.kernel.org/intel-gfx/20260212004852.1920270-1-khaled.almahallawy@intel.com/


Tested-by: default avatarKhaled Almahallawy <khaled.almahallawy@intel.com>
Fixes: 6a01df2f ("drm/i915: Remove pointless visible check in unlink_nv12_plane()")
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260316163953.12905-2-ville.syrjala@linux.intel.com


Reviewed-by: default avatarUma Shankar <uma.shankar@intel.com>
(cherry picked from commit 017ecd04)
Signed-off-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
parent 6ad2a661

drivers/gpu/drm/i915/display/intel_plane.c

+9 −2
Original line number Diff line number Diff line
@@ -436,11 +436,16 @@ void intel_plane_copy_hw_state(struct intel_plane_state *plane_state, 
		drm_framebuffer_get(plane_state->hw.fb);

}



static void unlink_nv12_plane(struct intel_crtc_state *crtc_state,

			      struct intel_plane_state *plane_state);



void intel_plane_set_invisible(struct intel_crtc_state *crtc_state,

			       struct intel_plane_state *plane_state)

{

	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);



	unlink_nv12_plane(crtc_state, plane_state);



	crtc_state->active_planes &= ~BIT(plane->id);

	crtc_state->scaled_planes &= ~BIT(plane->id);

	crtc_state->nv12_planes &= ~BIT(plane->id);
@@ -1513,6 +1518,9 @@ static void unlink_nv12_plane(struct intel_crtc_state *crtc_state, 
	struct intel_display *display = to_intel_display(plane_state);

	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);



	if (!plane_state->planar_linked_plane)

		return;



	plane_state->planar_linked_plane = NULL;



	if (!plane_state->is_y_plane)
@@ -1550,7 +1558,6 @@ static int icl_check_nv12_planes(struct intel_atomic_state *state, 
		if (plane->pipe != crtc->pipe)

			continue;



		if (plane_state->planar_linked_plane)

		unlink_nv12_plane(crtc_state, plane_state);

	}