| Message ID | 20241017162054.2701638-1-olvaffe@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/syncobj: ensure progress for syncobj queries | expand |
On Thu, 17 Oct 2024 09:20:53 -0700 Chia-I Wu <olvaffe@gmail.com> wrote: > Userspace might poll a syncobj with the query ioctl. Call > dma_fence_enable_sw_signaling to ensure dma_fence_is_signaled returns > true in finite time. > > --- > > panvk hits this issue when timeline semaphore is enabled. It uses the > transfer ioctl to propagate fences. dma_fence_unwrap_merge converts the > dma_fence_chain to a dma_fence_array. dma_fence_array_signaled never > return true unless signaling is enabled. Looks like a bugfix to me. Should we add Fixes+Cc-stable tags so it gets backported to stable branches. > --- > drivers/gpu/drm/drm_syncobj.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c > index 4fcfc0b9b386c..58c5593c897a2 100644 > --- a/drivers/gpu/drm/drm_syncobj.c > +++ b/drivers/gpu/drm/drm_syncobj.c > @@ -1689,6 +1689,9 @@ int drm_syncobj_query_ioctl(struct drm_device *dev, void *data, > DRM_SYNCOBJ_QUERY_FLAGS_LAST_SUBMITTED) { > point = fence->seqno; > } else { > + /* ensure forward progress */ > + dma_fence_enable_sw_signaling(fence); > + > dma_fence_chain_for_each(iter, fence) { > if (iter->context != fence->context) { > dma_fence_put(iter);
On Tue, Oct 22, 2024 at 3:30 AM Boris Brezillon <boris.brezillon@collabora.com> wrote: > > On Thu, 17 Oct 2024 09:20:53 -0700 > Chia-I Wu <olvaffe@gmail.com> wrote: > > > Userspace might poll a syncobj with the query ioctl. Call > > dma_fence_enable_sw_signaling to ensure dma_fence_is_signaled returns > > true in finite time. > > > > --- > > > > panvk hits this issue when timeline semaphore is enabled. It uses the > > transfer ioctl to propagate fences. dma_fence_unwrap_merge converts the > > dma_fence_chain to a dma_fence_array. dma_fence_array_signaled never > > return true unless signaling is enabled. > > Looks like a bugfix to me. Should we add Fixes+Cc-stable tags so it > gets backported to stable branches. Thanks. v2 sent with the Fixes tag. I did not add Cc-stable because I was told it was the maintainers' decision last time.
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 4fcfc0b9b386c..58c5593c897a2 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -1689,6 +1689,9 @@ int drm_syncobj_query_ioctl(struct drm_device *dev, void *data, DRM_SYNCOBJ_QUERY_FLAGS_LAST_SUBMITTED) { point = fence->seqno; } else { + /* ensure forward progress */ + dma_fence_enable_sw_signaling(fence); + dma_fence_chain_for_each(iter, fence) { if (iter->context != fence->context) { dma_fence_put(iter);