This is a note to let you know that I've just added the patch titled drm/i915: Flush pipecontrol post-sync writes to the 4.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-i915-flush-pipecontrol-post-sync-writes.patch and it can be found in the queue-4.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 40a24488f5250d63341e74b9994159afc4589606 Mon Sep 17 00:00:00 2001 From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Date: Fri, 21 Aug 2015 16:08:41 +0100 Subject: drm/i915: Flush pipecontrol post-sync writes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> commit 40a24488f5250d63341e74b9994159afc4589606 upstream. In order to flush the results from in-batch pipecontrol writes (used for example in glQuery) before declaring the batch complete (and so declaring the query results coherent), we need to set the FlushEnable bit in our flushing pipecontrol. The FlushEnable bit "waits until all previous writes of immediate data from post-sync circles are complete before executing the next command". I get GPU hangs on byt without flushing these writes (running ue4). piglit has examples where the flush is required for correct rendering. Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Acked-by: Daniel Vetter <daniel@xxxxxxxx> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/intel_lrc.c | 1 + drivers/gpu/drm/i915/intel_ringbuffer.c | 2 ++ 2 files changed, 3 insertions(+) --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1250,6 +1250,7 @@ static int gen8_emit_flush_render(struct if (flush_domains) { flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH; flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH; + flags |= PIPE_CONTROL_FLUSH_ENABLE; } if (invalidate_domains) { --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -342,6 +342,7 @@ gen7_render_ring_flush(struct intel_engi if (flush_domains) { flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH; flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH; + flags |= PIPE_CONTROL_FLUSH_ENABLE; } if (invalidate_domains) { flags |= PIPE_CONTROL_TLB_INVALIDATE; @@ -412,6 +413,7 @@ gen8_render_ring_flush(struct intel_engi if (flush_domains) { flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH; flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH; + flags |= PIPE_CONTROL_FLUSH_ENABLE; } if (invalidate_domains) { flags |= PIPE_CONTROL_TLB_INVALIDATE; Patches currently in stable-queue which might be from chris@xxxxxxxxxxxxxxxxxx are queue-4.2/drm-i915-flush-pipecontrol-post-sync-writes.patch queue-4.2/drm-i915-deny-wrapping-an-userptr-into-a-framebuffer.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html