From 8e792f018e10e68f488f279fbd4f38009a2e066d Mon Sep 17 00:00:00 2001 From: Matthew Schwartz Date: Thu, 11 Jun 2026 08:44:38 -0700 Subject: [PATCH] drm/amd/display: Fix mem_type change detection for async flips [Why] amdgpu_dm_crtc_mem_type_changed() fetches the "old" and "new" plane state with two drm_atomic_get_plane_state() calls, which both return the new state. It compares a state against itself, so it never detects a mem_type change and never rejects the async flip. On DCN 3.0.1, this shows up as intermittent corruption when a single DCC plane is scanned out with immediate flips under gamescope and its buffer moves between the VRAM carveout and GTT. [How] Use drm_atomic_get_old_plane_state() and drm_atomic_get_new_plane_state() to compare the actual old and new states. These return NULL rather than an error pointer for a plane that is not part of the commit, so the IS_ERR() check becomes a NULL check that skips those planes, such as an unmodified cursor still in the CRTC's plane_mask. Fixes: 4caacd1671b7 ("drm/amd/display: Do not elevate mem_type change to full update") Reviewed-by: Harry Wentland Reviewed-by: Melissa Wen Signed-off-by: Matthew Schwartz Signed-off-by: Alex Deucher (cherry picked from commit 13158e5dbd896281f3e9982b5437cffa5fd621b2) --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 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 1ed697a3a453..eb5696b5daeb 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -12938,13 +12938,11 @@ static bool amdgpu_dm_crtc_mem_type_changed(struct drm_device *dev, struct drm_plane_state *new_plane_state, *old_plane_state; drm_for_each_plane_mask(plane, dev, crtc_state->plane_mask) { - new_plane_state = drm_atomic_get_plane_state(state, plane); - old_plane_state = drm_atomic_get_plane_state(state, plane); + new_plane_state = drm_atomic_get_new_plane_state(state, plane); + old_plane_state = drm_atomic_get_old_plane_state(state, plane); - if (IS_ERR(new_plane_state) || IS_ERR(old_plane_state)) { - drm_err(dev, "Failed to get plane state for plane %s\n", plane->name); - return false; - } + if (!old_plane_state || !new_plane_state) + continue; if (old_plane_state->fb && new_plane_state->fb && get_mem_type(old_plane_state->fb) != get_mem_type(new_plane_state->fb))