linux-kernel - [PATCH v2] drm/amd/display: ensure async flips are only accepted for fast updates

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Message-ID: <20230804182054.142988-1-hamza.mahfooz@amd.com>
Date:   Fri, 4 Aug 2023 14:20:51 -0400
From:   Hamza Mahfooz <hamza.mahfooz@....com>
To:     <amd-gfx@...ts.freedesktop.org>
CC:     Hamza Mahfooz <hamza.mahfooz@....com>, <stable@...r.kernel.org>,
        "Harry Wentland" <harry.wentland@....com>,
        Leo Li <sunpeng.li@....com>,
        "Rodrigo Siqueira" <Rodrigo.Siqueira@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Qingqing Zhuo <qingqing.zhuo@....com>,
        Aurabindo Pillai <aurabindo.pillai@....com>,
        "Hersen Wu" <hersenxs.wu@....com>,
        Srinivasan Shanmugam <srinivasan.shanmugam@....com>,
        Stylon Wang <stylon.wang@....com>,
        Wayne Lin <wayne.lin@....com>, Alan Liu <haoping.liu@....com>,
        Melissa Wen <mwen@...lia.com>, Simon Ser <contact@...rsion.fr>,
        David Tadokoro <davidbtadokoro@....br>,
        André Almeida <andrealmeid@...lia.com>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] drm/amd/display: ensure async flips are only accepted for fast updates

We should be checking to see if async flips are supported in
amdgpu_dm_atomic_check() (i.e. not dm_crtc_helper_atomic_check()). Also,
async flipping isn't supported if a plane's framebuffer changes memory
domains during an atomic commit. So, move the check from
dm_crtc_helper_atomic_check() to amdgpu_dm_atomic_check() and check if
the memory domain has changed in amdgpu_dm_atomic_check().

Cc: stable@...r.kernel.org
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2733
Fixes: 3f86b60691e6 ("drm/amd/display: only accept async flips for fast updates")
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@....com>
---
v2: link issue and revert back to the old way of setting update_type.
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 24 ++++++++++++++++---
 .../amd/display/amdgpu_dm/amdgpu_dm_crtc.c    | 12 ----------
 2 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 32fb551862b0..1d3afab5bc85 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -8086,10 +8086,12 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
 		 * fast updates.
 		 */
 		if (crtc->state->async_flip &&
-		    acrtc_state->update_type != UPDATE_TYPE_FAST)
+		    (acrtc_state->update_type != UPDATE_TYPE_FAST ||
+		     get_mem_type(old_plane_state->fb) != get_mem_type(fb)))
 			drm_warn_once(state->dev,
 				      "[PLANE:%d:%s] async flip with non-fast update\n",
 				      plane->base.id, plane->name);
+
 		bundle->flip_addrs[planes_count].flip_immediate =
 			crtc->state->async_flip &&
 			acrtc_state->update_type == UPDATE_TYPE_FAST &&
@@ -10050,6 +10052,11 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 
 	/* Remove exiting planes if they are modified */
 	for_each_oldnew_plane_in_state_reverse(state, plane, old_plane_state, new_plane_state, i) {
+		if (old_plane_state->fb && new_plane_state->fb &&
+		    get_mem_type(old_plane_state->fb) !=
+		    get_mem_type(new_plane_state->fb))
+			lock_and_validation_needed = true;
+
 		ret = dm_update_plane_state(dc, state, plane,
 					    old_plane_state,
 					    new_plane_state,
@@ -10297,9 +10304,20 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 		struct dm_crtc_state *dm_new_crtc_state =
 			to_dm_crtc_state(new_crtc_state);
 
+		/*
+		 * Only allow async flips for fast updates that don't change
+		 * the FB pitch, the DCC state, rotation, etc.
+		 */
+		if (new_crtc_state->async_flip && lock_and_validation_needed) {
+			drm_dbg_atomic(crtc->dev,
+				       "[CRTC:%d:%s] async flips are only supported for fast updates\n",
+				       crtc->base.id, crtc->name);
+			ret = -EINVAL;
+			goto fail;
+		}
+
 		dm_new_crtc_state->update_type = lock_and_validation_needed ?
-							 UPDATE_TYPE_FULL :
-							 UPDATE_TYPE_FAST;
+			UPDATE_TYPE_FULL : UPDATE_TYPE_FAST;
 	}
 
 	/* Must be success */
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
index 30d4c6fd95f5..440fc0869a34 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
@@ -398,18 +398,6 @@ static int dm_crtc_helper_atomic_check(struct drm_crtc *crtc,
 		return -EINVAL;
 	}
 
-	/*
-	 * Only allow async flips for fast updates that don't change the FB
-	 * pitch, the DCC state, rotation, etc.
-	 */
-	if (crtc_state->async_flip &&
-	    dm_crtc_state->update_type != UPDATE_TYPE_FAST) {
-		drm_dbg_atomic(crtc->dev,
-			       "[CRTC:%d:%s] async flips are only supported for fast updates\n",
-			       crtc->base.id, crtc->name);
-		return -EINVAL;
-	}
-
 	/* In some use cases, like reset, no stream is attached */
 	if (!dm_crtc_state->stream)
 		return 0;
-- 
2.41.0