From: Wang Jiang Date: Wed, 29 Jul 2026 10:26:26 +0000 (+0800) Subject: drm/radeon: restore hardware polling in fence_is_signaled to fix performance regression X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=5f08eee9c3fb1a5a70966612e0ff249900f8e77b;p=thirdparty%2Fkernel%2Flinux.git drm/radeon: restore hardware polling in fence_is_signaled to fix performance regression Commit 527ba26e50ec ("drm/radeon: delete radeon_fence_process in is_signaled, no deadlock") removed the hardware polling from radeon_fence_is_signaled() to fix a self-deadlock caused by wake_up_all(&rdev->fence_queue) being called with the fence queue lock held. However, removing the polling entirely causes significant performance regression (e.g. glxgears FPS drop) because the fence signaled check becomes purely passive — it only reads the cached last_seq without probing the GPU, so completed GPU work is not detected in time, causing unnecessary CPU stalls in sync-heavy workloads. Fix this by calling radeon_fence_activity() directly instead of radeon_fence_process(). radeon_fence_activity() reads the hardware fence counter and updates last_seq via atomic ops without calling wake_up_all(), thus avoiding the deadlock while restoring timely fence detection. Fixes: 527ba26e50ec ("drm/radeon: delete radeon_fence_process in is_signaled, no deadlock") Acked-by: Christian König Signed-off-by: Wang Jiang Signed-off-by: Alex Deucher (cherry picked from commit f59ad4cca219c7fdf934f712c5860ec5f5900fd7) Cc: stable@vger.kernel.org --- diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c index 02a40e4750c7d..299865569252d 100644 --- a/drivers/gpu/drm/radeon/radeon_fence.c +++ b/drivers/gpu/drm/radeon/radeon_fence.c @@ -360,6 +360,13 @@ static bool radeon_fence_is_signaled(struct dma_fence *f) if (atomic64_read(&rdev->fence_drv[ring].last_seq) >= seq) return true; + if (down_read_trylock(&rdev->exclusive_lock)) { + radeon_fence_activity(rdev, ring); + up_read(&rdev->exclusive_lock); + + if (atomic64_read(&rdev->fence_drv[ring].last_seq) >= seq) + return true; + } return false; }