TTM, GEM, DRM or the core DMA-buf framework are needs to enable software signaling before the fence is signaled. The core DMA-buf framework software can forget to call enable_signaling before the fence is signaled. It means framework code can forget to call dma_fence_enable_sw_signaling() before calling dma_fence_is_signaled(). To avoid this scenario on debug kernel, check the DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT bit status before checking the MA_FENCE_FLAG_SIGNALED_BIT bit status to confirm that software signaling is enabled.
Arvind Yadav (4): dma-buf: Check status of enable-signaling bit on debug drm/sched: Add callback and enable signaling on debug dma-buf: Add callback and enable signaling on debug dma-buf: Add callback and enable signaling on debug
drivers/dma-buf/dma-fence.c | 17 ++++++++ drivers/dma-buf/st-dma-fence-chain.c | 17 ++++++++ drivers/dma-buf/st-dma-fence-unwrap.c | 54 +++++++++++++++++++++++++ drivers/dma-buf/st-dma-fence.c | 34 +++++++++++++++- drivers/dma-buf/st-dma-resv.c | 30 ++++++++++++++ drivers/gpu/drm/scheduler/sched_fence.c | 12 ++++++ drivers/gpu/drm/scheduler/sched_main.c | 4 +- include/linux/dma-fence.h | 5 +++ 8 files changed, 171 insertions(+), 2 deletions(-)