From: jsg <jsg@openbsd.org>
Date: Fri, 28 Jul 2023 06:39:54 +0000 (+0000)
Subject: drm/amd/display: only accept async flips for fast updates
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=db580b7bb85073a120c216d8324451316a078d18;p=openbsd

drm/amd/display: only accept async flips for fast updates

From Simon Ser
4385420741743247a7bdedb5c0b1eb5efe9a9edd in linux-6.1.y/6.1.42
1ca67aba8d11c2849d395013e1fdce02918d5657 in mainline linux
---

diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 21e07a101aa..39e027e36ae 100644
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7761,7 +7761,15 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
 		 * Only allow immediate flips for fast updates that don't
 		 * change memory domain, FB pitch, DCC state, rotation or
 		 * mirroring.
+		 *
+		 * dm_crtc_helper_atomic_check() only accepts async flips with
+		 * fast updates.
 		 */
+		if (crtc->state->async_flip &&
+		    acrtc_state->update_type != UPDATE_TYPE_FAST)
+			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 &&
diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
index 1ec643a0d00..b9b70f4562c 100644
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
@@ -406,6 +406,18 @@ 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;