| Message ID | 20220603211849.27703-3-dongwon.kim@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/virtio: fence handling in case of multi scanouts | expand |
Hi DW, > Subject: [PATCH v2 2/2] drm/virtio: fence created per cursor/plane update > > Having one fence for a vgfb would cause conflict in case there are > multiple planes referencing the same vgfb (e.g. Xorg screen covering > two displays in extended mode) being flushed simultaneously. So it makes > sence to use a separated fence for each plane update to prevent this. > > vgfb->fence is not required anymore with the suggested code change so > both prepare_fb and cleanup_fb are removed since only fence creation/ > freeing are done in there. > > v2: - use the fence always as long as guest_blob is enabled on the > scanout object > - obj and fence initialized as NULL ptrs to avoid uninitialzed > ptr problem (Reported by Dan Carpenter/kernel-test-robot) > > Reported-by: kernel test robot <lkp@intel.com> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > Cc: Gurchetan Singh <gurchetansingh@chromium.org> > Cc: Gerd Hoffmann <kraxel@redhat.com> > Cc: Vivek Kasireddy <vivek.kasireddy@intel.com> > Signed-off-by: Dongwon Kim <dongwon.kim@intel.com> > --- > drivers/gpu/drm/virtio/virtgpu_drv.h | 1 - > drivers/gpu/drm/virtio/virtgpu_plane.c | 103 ++++++++++--------------- > 2 files changed, 39 insertions(+), 65 deletions(-) > > diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h > index 0a194aaad419..4c59c1e67ca5 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_drv.h > +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h > @@ -186,7 +186,6 @@ struct virtio_gpu_output { > > struct virtio_gpu_framebuffer { > struct drm_framebuffer base; > - struct virtio_gpu_fence *fence; > }; > #define to_virtio_gpu_framebuffer(x) \ > container_of(x, struct virtio_gpu_framebuffer, base) > diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c > index 6d3cc9e238a4..821023b7d57d 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_plane.c > +++ b/drivers/gpu/drm/virtio/virtgpu_plane.c > @@ -137,29 +137,37 @@ static void virtio_gpu_resource_flush(struct drm_plane *plane, > struct virtio_gpu_device *vgdev = dev->dev_private; > struct virtio_gpu_framebuffer *vgfb; > struct virtio_gpu_object *bo; > + struct virtio_gpu_object_array *objs = NULL; > + struct virtio_gpu_fence *fence = NULL; > > vgfb = to_virtio_gpu_framebuffer(plane->state->fb); > bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]); > - if (vgfb->fence) { > - struct virtio_gpu_object_array *objs; > > + if (!bo) > + return; [Kasireddy, Vivek] I think you can drop the above check as bo is guaranteed to be valid in resource_flush as the necessary checks are already done early in virtio_gpu_primary_plane_update(). > + > + if (bo->dumb && bo->guest_blob) > + fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, > + 0); > + > + if (fence) { > objs = virtio_gpu_array_alloc(1); > - if (!objs) > + if (!objs) { > + kfree(fence); > return; > + } > virtio_gpu_array_add_obj(objs, vgfb->base.obj[0]); > virtio_gpu_array_lock_resv(objs); > - virtio_gpu_cmd_resource_flush(vgdev, bo->hw_res_handle, x, y, > - width, height, objs, vgfb->fence); > - virtio_gpu_notify(vgdev); > + } > + > + virtio_gpu_cmd_resource_flush(vgdev, bo->hw_res_handle, x, y, > + width, height, objs, fence); > + virtio_gpu_notify(vgdev); [Kasireddy, Vivek] I think it is OK to retain the existing style where all the statements relevant for if (fence) would be lumped together. I do understand that the above two statements would be redundant in that case but it looks a bit cleaner. > > - dma_fence_wait_timeout(&vgfb->fence->f, true, > + if (fence) { > + dma_fence_wait_timeout(&fence->f, true, > msecs_to_jiffies(50)); > - dma_fence_put(&vgfb->fence->f); > - vgfb->fence = NULL; > - } else { > - virtio_gpu_cmd_resource_flush(vgdev, bo->hw_res_handle, x, y, > - width, height, NULL, NULL); > - virtio_gpu_notify(vgdev); > + dma_fence_put(&fence->f); > } > } > > @@ -239,47 +247,6 @@ static void virtio_gpu_primary_plane_update(struct drm_plane > *plane, > rect.y2 - rect.y1); > } > > -static int virtio_gpu_plane_prepare_fb(struct drm_plane *plane, > - struct drm_plane_state *new_state) > -{ > - struct drm_device *dev = plane->dev; > - struct virtio_gpu_device *vgdev = dev->dev_private; > - struct virtio_gpu_framebuffer *vgfb; > - struct virtio_gpu_object *bo; > - > - if (!new_state->fb) > - return 0; > - > - vgfb = to_virtio_gpu_framebuffer(new_state->fb); > - bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]); > - if (!bo || (plane->type == DRM_PLANE_TYPE_PRIMARY && !bo->guest_blob)) > - return 0; > - > - if (bo->dumb && (plane->state->fb != new_state->fb)) { > - vgfb->fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, > - 0); > - if (!vgfb->fence) > - return -ENOMEM; > - } > - > - return 0; > -} > - > -static void virtio_gpu_plane_cleanup_fb(struct drm_plane *plane, > - struct drm_plane_state *old_state) > -{ > - struct virtio_gpu_framebuffer *vgfb; > - > - if (!plane->state->fb) > - return; > - > - vgfb = to_virtio_gpu_framebuffer(plane->state->fb); > - if (vgfb->fence) { > - dma_fence_put(&vgfb->fence->f); > - vgfb->fence = NULL; > - } > -} > - > static void virtio_gpu_cursor_plane_update(struct drm_plane *plane, > struct drm_atomic_state *state) > { > @@ -290,6 +257,8 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane > *plane, > struct virtio_gpu_output *output = NULL; > struct virtio_gpu_framebuffer *vgfb; > struct virtio_gpu_object *bo = NULL; > + struct virtio_gpu_object_array *objs = NULL; > + struct virtio_gpu_fence *fence = NULL; > uint32_t handle; > > if (plane->state->crtc) > @@ -309,22 +278,32 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane > *plane, > > if (bo && bo->dumb && (plane->state->fb != old_state->fb)) { > /* new cursor -- update & wait */ > - struct virtio_gpu_object_array *objs; > + fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, > + 0); > + if (!fence) > + return; > > objs = virtio_gpu_array_alloc(1); > - if (!objs) > + if (!objs) { > + if (fence) [Kasireddy, Vivek] I think you can drop the above check given that you checked it earlier. > + kfree(fence); > + > return; > + } > + > virtio_gpu_array_add_obj(objs, vgfb->base.obj[0]); > virtio_gpu_array_lock_resv(objs); > virtio_gpu_cmd_transfer_to_host_2d > (vgdev, 0, > plane->state->crtc_w, > plane->state->crtc_h, > - 0, 0, objs, vgfb->fence); > + 0, 0, objs, fence); > virtio_gpu_notify(vgdev); > - dma_fence_wait(&vgfb->fence->f, true); > - dma_fence_put(&vgfb->fence->f); > - vgfb->fence = NULL; > + > + if (fence) { [Kasireddy, Vivek] Same as above; i.e, you can drop the if (fence) check as we wouldn't get here without a valid fence. I think with the above changes, the diff may get smaller and simpler. Regardless, this patch is Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com> > + dma_fence_wait(&fence->f, true); > + dma_fence_put(&fence->f); > + } > } > > if (plane->state->fb != old_state->fb) { > @@ -358,15 +337,11 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane > *plane, > } > > static const struct drm_plane_helper_funcs virtio_gpu_primary_helper_funcs = { > - .prepare_fb = virtio_gpu_plane_prepare_fb, > - .cleanup_fb = virtio_gpu_plane_cleanup_fb, > .atomic_check = virtio_gpu_plane_atomic_check, > .atomic_update = virtio_gpu_primary_plane_update, > }; > > static const struct drm_plane_helper_funcs virtio_gpu_cursor_helper_funcs = { > - .prepare_fb = virtio_gpu_plane_prepare_fb, > - .cleanup_fb = virtio_gpu_plane_cleanup_fb, > .atomic_check = virtio_gpu_plane_atomic_check, > .atomic_update = virtio_gpu_cursor_plane_update, > }; > -- > 2.20.1
On Fri, Jun 03, 2022 at 02:18:49PM -0700, Dongwon Kim wrote: > Having one fence for a vgfb would cause conflict in case there are > multiple planes referencing the same vgfb (e.g. Xorg screen covering > two displays in extended mode) being flushed simultaneously. So it makes > sence to use a separated fence for each plane update to prevent this. > > vgfb->fence is not required anymore with the suggested code change so > both prepare_fb and cleanup_fb are removed since only fence creation/ > freeing are done in there. The fences are allocated and released in prepare_fb + cleanup_fb for a reason: atomic_update must not fail. I guess virtio-gpu must be fixed to use drm_plane_state->fence correctly ... take care, Gerd
On Thu, Jun 09, 2022 at 06:24:43AM +0200, Gerd Hoffmann wrote: > On Fri, Jun 03, 2022 at 02:18:49PM -0700, Dongwon Kim wrote: > > Having one fence for a vgfb would cause conflict in case there are > > multiple planes referencing the same vgfb (e.g. Xorg screen covering > > two displays in extended mode) being flushed simultaneously. So it makes > > sence to use a separated fence for each plane update to prevent this. > > > > vgfb->fence is not required anymore with the suggested code change so > > both prepare_fb and cleanup_fb are removed since only fence creation/ > > freeing are done in there. > > The fences are allocated and released in prepare_fb + cleanup_fb for a > reason: atomic_update must not fail. In case fence allocation fails, it falls back to non-fence path so it won't fail for primary-plane-update. For cursor plane update, it returns if fence is NULL but we could change it to just proceed and just make it skip waiting like, if (fence) { dma_fence_wait(&fence->f, true); dma_fence_put(&fence->f); } Or maybe I can limit my suggested changes to primary-plane-update only. What do you think about these? > > I guess virtio-gpu must be fixed to use drm_plane_state->fence > correctly ... I was thinking about this too but current functions (e.g. virtio_gpu_cmd_transfer_to_host_2d) takes "struct virtio_gpu_fence". Not sure what is the best way to connect drm_plane_state->fence to virtio_gpu_fence without changing major function interfaces. > > take care, > Gerd >
Hi DW, > > On Thu, Jun 09, 2022 at 06:24:43AM +0200, Gerd Hoffmann wrote: > > On Fri, Jun 03, 2022 at 02:18:49PM -0700, Dongwon Kim wrote: > > > Having one fence for a vgfb would cause conflict in case there are > > > multiple planes referencing the same vgfb (e.g. Xorg screen covering > > > two displays in extended mode) being flushed simultaneously. So it makes > > > sence to use a separated fence for each plane update to prevent this. > > > > > > vgfb->fence is not required anymore with the suggested code change so > > > both prepare_fb and cleanup_fb are removed since only fence creation/ > > > freeing are done in there. > > > > The fences are allocated and released in prepare_fb + cleanup_fb for a > > reason: atomic_update must not fail. > > In case fence allocation fails, it falls back to non-fence path so it > won't fail for primary-plane-update. > > For cursor plane update, it returns if fence is NULL but we could change > it to just proceed and just make it skip waiting like, [Kasireddy, Vivek] But cursor plane update is always tied to a fence based on the way it works now and we have to fail if there is no fence. > > if (fence) { > dma_fence_wait(&fence->f, true); > dma_fence_put(&fence->f); > } > > Or maybe I can limit my suggested changes to primary-plane-update only. > > What do you think about these? > > > > > I guess virtio-gpu must be fixed to use drm_plane_state->fence > > correctly ... > > I was thinking about this too but current functions (e.g. > virtio_gpu_cmd_transfer_to_host_2d) takes "struct virtio_gpu_fence". > Not sure what is the best way to connect drm_plane_state->fence to > virtio_gpu_fence without changing major function interfaces. [Kasireddy, Vivek] FWIU, we cannot use drm_plane_state->fence as it is used by drm core to handle explicit fences. So, I think a cleaner way is to subclass base drm_plane_state and move the fence from virtio_gpu_framebuffer to a new struct virtio_gpu_plane_state. This way, we can create the fence in prepare_fb() and use it for synchronization in resource_flush. Thanks, Vivek > > > > > take care, > > Gerd > >
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h index 0a194aaad419..4c59c1e67ca5 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.h +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h @@ -186,7 +186,6 @@ struct virtio_gpu_output { struct virtio_gpu_framebuffer { struct drm_framebuffer base; - struct virtio_gpu_fence *fence; }; #define to_virtio_gpu_framebuffer(x) \ container_of(x, struct virtio_gpu_framebuffer, base) diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c index 6d3cc9e238a4..821023b7d57d 100644 --- a/drivers/gpu/drm/virtio/virtgpu_plane.c +++ b/drivers/gpu/drm/virtio/virtgpu_plane.c @@ -137,29 +137,37 @@ static void virtio_gpu_resource_flush(struct drm_plane *plane, struct virtio_gpu_device *vgdev = dev->dev_private; struct virtio_gpu_framebuffer *vgfb; struct virtio_gpu_object *bo; + struct virtio_gpu_object_array *objs = NULL; + struct virtio_gpu_fence *fence = NULL; vgfb = to_virtio_gpu_framebuffer(plane->state->fb); bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]); - if (vgfb->fence) { - struct virtio_gpu_object_array *objs; + if (!bo) + return; + + if (bo->dumb && bo->guest_blob) + fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, + 0); + + if (fence) { objs = virtio_gpu_array_alloc(1); - if (!objs) + if (!objs) { + kfree(fence); return; + } virtio_gpu_array_add_obj(objs, vgfb->base.obj[0]); virtio_gpu_array_lock_resv(objs); - virtio_gpu_cmd_resource_flush(vgdev, bo->hw_res_handle, x, y, - width, height, objs, vgfb->fence); - virtio_gpu_notify(vgdev); + } + + virtio_gpu_cmd_resource_flush(vgdev, bo->hw_res_handle, x, y, + width, height, objs, fence); + virtio_gpu_notify(vgdev); - dma_fence_wait_timeout(&vgfb->fence->f, true, + if (fence) { + dma_fence_wait_timeout(&fence->f, true, msecs_to_jiffies(50)); - dma_fence_put(&vgfb->fence->f); - vgfb->fence = NULL; - } else { - virtio_gpu_cmd_resource_flush(vgdev, bo->hw_res_handle, x, y, - width, height, NULL, NULL); - virtio_gpu_notify(vgdev); + dma_fence_put(&fence->f); } } @@ -239,47 +247,6 @@ static void virtio_gpu_primary_plane_update(struct drm_plane *plane, rect.y2 - rect.y1); } -static int virtio_gpu_plane_prepare_fb(struct drm_plane *plane, - struct drm_plane_state *new_state) -{ - struct drm_device *dev = plane->dev; - struct virtio_gpu_device *vgdev = dev->dev_private; - struct virtio_gpu_framebuffer *vgfb; - struct virtio_gpu_object *bo; - - if (!new_state->fb) - return 0; - - vgfb = to_virtio_gpu_framebuffer(new_state->fb); - bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]); - if (!bo || (plane->type == DRM_PLANE_TYPE_PRIMARY && !bo->guest_blob)) - return 0; - - if (bo->dumb && (plane->state->fb != new_state->fb)) { - vgfb->fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, - 0); - if (!vgfb->fence) - return -ENOMEM; - } - - return 0; -} - -static void virtio_gpu_plane_cleanup_fb(struct drm_plane *plane, - struct drm_plane_state *old_state) -{ - struct virtio_gpu_framebuffer *vgfb; - - if (!plane->state->fb) - return; - - vgfb = to_virtio_gpu_framebuffer(plane->state->fb); - if (vgfb->fence) { - dma_fence_put(&vgfb->fence->f); - vgfb->fence = NULL; - } -} - static void virtio_gpu_cursor_plane_update(struct drm_plane *plane, struct drm_atomic_state *state) { @@ -290,6 +257,8 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane *plane, struct virtio_gpu_output *output = NULL; struct virtio_gpu_framebuffer *vgfb; struct virtio_gpu_object *bo = NULL; + struct virtio_gpu_object_array *objs = NULL; + struct virtio_gpu_fence *fence = NULL; uint32_t handle; if (plane->state->crtc) @@ -309,22 +278,32 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane *plane, if (bo && bo->dumb && (plane->state->fb != old_state->fb)) { /* new cursor -- update & wait */ - struct virtio_gpu_object_array *objs; + fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, + 0); + if (!fence) + return; objs = virtio_gpu_array_alloc(1); - if (!objs) + if (!objs) { + if (fence) + kfree(fence); + return; + } + virtio_gpu_array_add_obj(objs, vgfb->base.obj[0]); virtio_gpu_array_lock_resv(objs); virtio_gpu_cmd_transfer_to_host_2d (vgdev, 0, plane->state->crtc_w, plane->state->crtc_h, - 0, 0, objs, vgfb->fence); + 0, 0, objs, fence); virtio_gpu_notify(vgdev); - dma_fence_wait(&vgfb->fence->f, true); - dma_fence_put(&vgfb->fence->f); - vgfb->fence = NULL; + + if (fence) { + dma_fence_wait(&fence->f, true); + dma_fence_put(&fence->f); + } } if (plane->state->fb != old_state->fb) { @@ -358,15 +337,11 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane *plane, } static const struct drm_plane_helper_funcs virtio_gpu_primary_helper_funcs = { - .prepare_fb = virtio_gpu_plane_prepare_fb, - .cleanup_fb = virtio_gpu_plane_cleanup_fb, .atomic_check = virtio_gpu_plane_atomic_check, .atomic_update = virtio_gpu_primary_plane_update, }; static const struct drm_plane_helper_funcs virtio_gpu_cursor_helper_funcs = { - .prepare_fb = virtio_gpu_plane_prepare_fb, - .cleanup_fb = virtio_gpu_plane_cleanup_fb, .atomic_check = virtio_gpu_plane_atomic_check, .atomic_update = virtio_gpu_cursor_plane_update, };
Having one fence for a vgfb would cause conflict in case there are multiple planes referencing the same vgfb (e.g. Xorg screen covering two displays in extended mode) being flushed simultaneously. So it makes sence to use a separated fence for each plane update to prevent this. vgfb->fence is not required anymore with the suggested code change so both prepare_fb and cleanup_fb are removed since only fence creation/ freeing are done in there. v2: - use the fence always as long as guest_blob is enabled on the scanout object - obj and fence initialized as NULL ptrs to avoid uninitialzed ptr problem (Reported by Dan Carpenter/kernel-test-robot) Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Gurchetan Singh <gurchetansingh@chromium.org> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Vivek Kasireddy <vivek.kasireddy@intel.com> Signed-off-by: Dongwon Kim <dongwon.kim@intel.com> --- drivers/gpu/drm/virtio/virtgpu_drv.h | 1 - drivers/gpu/drm/virtio/virtgpu_plane.c | 103 ++++++++++--------------- 2 files changed, 39 insertions(+), 65 deletions(-)