6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ian Forbes <ian.forbes@xxxxxxxxxxxx>
[ Upstream commit 5703fc058efdafcdd6b70776ee562478f0753acb ]
These pointers are frequently the same and memcmp does not compare the
pointers before comparing their contents so this was wasting cycles
comparing 16 KiB of memory which will always be equal.
Fixes: bb6780aa5a1d ("drm/vmwgfx: Diff cursors when using cmds")
Signed-off-by: Ian Forbes <ian.forbes@xxxxxxxxxxxx>
Signed-off-by: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240328190716.27367-1-ian.forbes@xxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 42fcf4698aba9..11755d143e657 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -216,7 +216,7 @@ static bool vmw_du_cursor_plane_has_changed(struct vmw_plane_state *old_vps,
new_image = vmw_du_cursor_plane_acquire_image(new_vps);
changed = false;
- if (old_image && new_image)
+ if (old_image && new_image && old_image != new_image)
changed = memcmp(old_image, new_image, size) != 0;
return changed;
--
2.43.0
