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From: Harry Wentland <harry.wentland@amd.com>
Date: Mon, 16 Apr 2018 17:28:11 -0400
Subject: drm/amd/display: Disallow enabling CRTC without primary plane with FB
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Git-commit: f2877656809386d7bc62c2b1c1b4e58404c486d4
Patch-mainline: v4.17-rc3
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

The below commit

    "drm/atomic: Try to preserve the crtc enabled state in drm_atomic_remove_fb, v2"

introduces a slight behavioral change to rmfb. Instead of disabling a crtc
when the primary plane is disabled, it now preserves it.

Since DC is currently not equipped to handle this we need to fail such
a commit, otherwise we might see a corrupted screen.

This is based on Shirish's previous approach but avoids adding all
planes to the new atomic state which leads to a full update in DC for
any commit, and is not what we intend.

Theoretically DM should be able to deal with states with fully populated planes,
even for simple updates, such as cursor updates. This should still be
addressed in the future.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4557,6 +4557,7 @@ static int dm_update_crtcs_state(struct
 		struct amdgpu_dm_connector *aconnector = NULL;
 		struct drm_connector_state *new_con_state = NULL;
 		struct dm_connector_state *dm_conn_state = NULL;
+		struct drm_plane_state *new_plane_state = NULL;
 
 		new_stream = NULL;
 
@@ -4564,6 +4565,13 @@ static int dm_update_crtcs_state(struct
 		dm_new_crtc_state = to_dm_crtc_state(new_crtc_state);
 		acrtc = to_amdgpu_crtc(crtc);
 
+		new_plane_state = drm_atomic_get_new_plane_state(state, new_crtc_state->crtc->primary);
+
+		if (new_crtc_state->enable && new_plane_state && !new_plane_state->fb) {
+			ret = -EINVAL;
+			goto fail;
+		}
+
 		aconnector = amdgpu_dm_find_first_crtc_matching_connector(state, crtc);
 
 		/* TODO This hack should go away */
@@ -4760,7 +4768,7 @@ static int dm_update_planes_state(struct
 			if (!dm_old_crtc_state->stream)
 				continue;
 
-			DRM_DEBUG_DRIVER("Disabling DRM plane: %d on DRM crtc %d\n",
+			DRM_DEBUG_ATOMIC("Disabling DRM plane: %d on DRM crtc %d\n",
 					plane->base.id, old_plane_crtc->base.id);
 
 			if (!dc_remove_plane_from_context(