drm/amd/display: fix flickering caused by S/G mode

commit 08da182175db4c7f80850354849d95f2670e8cd9 upstream.

Currently, on a handful of ASICs. We allow the framebuffer for a given
plane to exist in either VRAM or GTT. However, if the plane's new
framebuffer is in a different memory domain than it's previous
framebuffer, flipping between them can cause the screen to flicker. So,
to fix this, don't perform an immediate flip in the aforementioned case.

Cc: stable@vger.kernel.org
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2354
Reviewed-by: Roman Li <Roman.Li@amd.com>
Fixes: 81d0bcf99009 ("drm/amdgpu: make display pinning more flexible (v2)")
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 85840491585104c98b485075c84143322fdf99ea..48338e315fd01ab0e37c9557cecafa97a0cf9953 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7593,6 +7593,13 @@ static void amdgpu_dm_commit_cursors(struct drm_atomic_state *state)
                        handle_cursor_update(plane, old_plane_state);
 }
 
+static inline uint32_t get_mem_type(struct drm_framebuffer *fb)
+{
+       struct amdgpu_bo *abo = gem_to_amdgpu_bo(fb->obj[0]);
+
+       return abo->tbo.resource ? abo->tbo.resource->mem_type : 0;
+}
+
 static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
                                    struct dc_state *dc_state,
                                    struct drm_device *dev,
@@ -7710,11 +7717,13 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
 
                /*
                 * Only allow immediate flips for fast updates that don't
-                * change FB pitch, DCC state, rotation or mirroing.
+                * change memory domain, FB pitch, DCC state, rotation or
+                * mirroring.
                 */
                bundle->flip_addrs[planes_count].flip_immediate =
                        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);
 
                timestamp_ns = ktime_get_ns();
                bundle->flip_addrs[planes_count].flip_timestamp_in_us = div_u64(timestamp_ns, 1000);