5.4-stable review patch. If anyone has any objections, please let me know.
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From: Erik Kurzinger ekurzinger@nvidia.com
[ Upstream commit 101c9f637efa1655f55876644d4439e552267527 ]
If DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT is invoked with the DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE flag set but no fence has yet been submitted for the given timeline point the call will fail immediately with EINVAL. This does not match the intended behavior where the call should wait until the fence has been submitted (or the timeout expires).
The following small example program illustrates the issue. It should wait for 5 seconds and then print ETIME, but instead it terminates right away after printing EINVAL.
#include <stdio.h> #include <fcntl.h> #include <time.h> #include <errno.h> #include <xf86drm.h> int main(void) { int fd = open("/dev/dri/card0", O_RDWR); uint32_t syncobj; drmSyncobjCreate(fd, 0, &syncobj); struct timespec ts; clock_gettime(CLOCK_MONOTONIC, &ts); uint64_t point = 1; if (drmSyncobjTimelineWait(fd, &syncobj, &point, 1, ts.tv_sec * 1000000000 + ts.tv_nsec + 5000000000, // 5s DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE, NULL)) { printf("drmSyncobjTimelineWait failed %d\n", errno); } }
Fixes: 01d6c3578379 ("drm/syncobj: add support for timeline point wait v8") Signed-off-by: Erik Kurzinger ekurzinger@nvidia.com Reviewed by: Simon Ser contact@emersion.fd Signed-off-by: Simon Ser contact@emersion.fr Link: https://patchwork.freedesktop.org/patch/msgid/1fac96f1-2f3f-f9f9-4eb0-340f27... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/drm_syncobj.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index e558381c4c96e..8b155e3377cfe 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -921,7 +921,8 @@ static signed long drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs, fence = drm_syncobj_fence_get(syncobjs[i]); if (!fence || dma_fence_chain_find_seqno(&fence, points[i])) { dma_fence_put(fence); - if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) { + if (flags & (DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT | + DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE)) { continue; } else { timeout = -EINVAL;