drm/amdgpu: fix waiting for all fences before flipping

Otherwise we might see corruption.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 7a3a00f..68beb40 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -828,7 +828,9 @@ struct amdgpu_flip_work {
        uint64_t                        base;
        struct drm_pending_vblank_event *event;
        struct amdgpu_bo                *old_rbo;
-       struct fence                    *fence;
+       struct fence                    *excl;
+       unsigned                        shared_count;
+       struct fence                    **shared;
 };
 
 

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
index e12931e..e3d7077 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
@@ -35,6 +35,36 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_edid.h>
 
+static void amdgpu_flip_wait_fence(struct amdgpu_device *adev,
+                                  struct fence **f)
+{
+       struct amdgpu_fence *fence;
+       long r;
+
+       if (*f == NULL)
+               return;
+
+       fence = to_amdgpu_fence(*f);
+       if (fence) {
+               r = fence_wait(&fence->base, false);
+               if (r == -EDEADLK) {
+                       up_read(&adev->exclusive_lock);
+                       r = amdgpu_gpu_reset(adev);
+                       down_read(&adev->exclusive_lock);
+               }
+       } else
+               r = fence_wait(*f, false);
+
+       if (r)
+               DRM_ERROR("failed to wait on page flip fence (%ld)!\n", r);
+
+       /* We continue with the page flip even if we failed to wait on
+        * the fence, otherwise the DRM core and userspace will be
+        * confused about which BO the CRTC is scanning out
+        */
+       fence_put(*f);
+       *f = NULL;
+}
 
 static void amdgpu_flip_work_func(struct work_struct *__work)
 {
@@ -44,34 +74,13 @@ static void amdgpu_flip_work_func(struct work_struct *__work)
        struct amdgpu_crtc *amdgpuCrtc = adev->mode_info.crtcs[work->crtc_id];
 
        struct drm_crtc *crtc = &amdgpuCrtc->base;
-       struct amdgpu_fence *fence;
        unsigned long flags;
-       int r;
+       unsigned i;
 
        down_read(&adev->exclusive_lock);
-       if (work->fence) {
-               fence = to_amdgpu_fence(work->fence);
-               if (fence) {
-                       r = fence_wait(&fence->base, false);
-                       if (r == -EDEADLK) {
-                               up_read(&adev->exclusive_lock);
-                               r = amdgpu_gpu_reset(adev);
-                               down_read(&adev->exclusive_lock);
-                       }
-               } else
-                       r = fence_wait(work->fence, false);
-
-               if (r)
-                       DRM_ERROR("failed to wait on page flip fence (%d)!\n", r);
-
-               /* We continue with the page flip even if we failed to wait on
-                * the fence, otherwise the DRM core and userspace will be
-                * confused about which BO the CRTC is scanning out
-                */
-
-               fence_put(work->fence);
-               work->fence = NULL;
-       }
+       amdgpu_flip_wait_fence(adev, &work->excl);
+       for (i = 0; i < work->shared_count; ++i)
+               amdgpu_flip_wait_fence(adev, &work->shared[i]);
 
        /* We borrow the event spin lock for protecting flip_status */
        spin_lock_irqsave(&crtc->dev->event_lock, flags);
@@ -108,6 +117,7 @@ static void amdgpu_unpin_work_func(struct work_struct *__work)
                DRM_ERROR("failed to reserve buffer after flip\n");
 
        drm_gem_object_unreference_unlocked(&work->old_rbo->gem_base);
+       kfree(work->shared);
        kfree(work);
 }
 
@@ -127,7 +137,7 @@ int amdgpu_crtc_page_flip(struct drm_crtc *crtc,
        unsigned long flags;
        u64 tiling_flags;
        u64 base;
-       int r;
+       int i, r;
 
        work = kzalloc(sizeof *work, GFP_KERNEL);
        if (work == NULL)
@@ -167,7 +177,19 @@ int amdgpu_crtc_page_flip(struct drm_crtc *crtc,
                goto cleanup;
        }
 
-       work->fence = fence_get(reservation_object_get_excl(new_rbo->tbo.resv));
+       r = reservation_object_get_fences_rcu(new_rbo->tbo.resv, &work->excl,
+                                             &work->shared_count,
+                                             &work->shared);
+       if (unlikely(r != 0)) {
+               amdgpu_bo_unreserve(new_rbo);
+               DRM_ERROR("failed to get fences for buffer\n");
+               goto cleanup;
+       }
+
+       fence_get(work->excl);
+       for (i = 0; i < work->shared_count; ++i)
+               fence_get(work->shared[i]);
+
        amdgpu_bo_get_tiling_flags(new_rbo, &tiling_flags);
        amdgpu_bo_unreserve(new_rbo);
 
@@ -212,7 +234,10 @@ pflip_cleanup:
 
 cleanup:
        drm_gem_object_unreference_unlocked(&work->old_rbo->gem_base);
-       fence_put(work->fence);
+       fence_put(work->excl);
+       for (i = 0; i < work->shared_count; ++i)
+               fence_put(work->shared[i]);
+       kfree(work->shared);
        kfree(work);
 
        return r;