On Sun, Apr 02, 2017 at 03:36:11PM +0100, Chris Wilson wrote: > A piece of magic that prevents Baytrail from doing a timewarp. (Perhaps > executing an incorrect portion of the ring?) If left to itself after a > few hundred resets, the GPU will write a stale seqno causing all > requests to be completed early and the GPU then appears idle. + stuck in the future > A msleep(1000) before the intel_gpu_reset, or after it is not > sufficient, but a short delay of a few hundred microseconds after (also demonstrating that this is not a stray write left inflight from before the reset) > writing the RING_CTL is. Less than a few hundred us, or inserting a few > more posting reads into the init_ring_common is not enough. To limit the > impact, it appears we only need one after all RING_CTL writes and also we > only want to apply it when writing nonzero values into the RING_HEAD/TAIL > i.e. after reset. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98836 Testcase: igt/gem_exec_whisper/hang-chain > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Before I forget to add them. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
