From b08b4b2b25b201df2d667cf70d7f99475e5c7aec Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Tue, 21 Aug 2018 20:40:50 -0500 Subject: [PATCH] anv: Disable the vertex cache when tessellating on SKL GT4 I have no idea if I'm correct about what's going wrong or if this is the correct fix. However, in my multiple weeks of banging my head on this hang, a VUE reference counting bug seems to match all the symptoms and it definitely fixes the hang. Cc: mesa-stable@lists.freedesktop.org Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107280 Reviewed-by: Kenneth Graunke --- src/intel/vulkan/genX_pipeline.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_pipeline.c index 297e945..9595a71 100644 --- a/src/intel/vulkan/genX_pipeline.c +++ b/src/intel/vulkan/genX_pipeline.c @@ -1173,7 +1173,28 @@ emit_3dstate_vs(struct anv_pipeline *pipeline) vs.IllegalOpcodeExceptionEnable = false; vs.SoftwareExceptionEnable = false; vs.MaximumNumberofThreads = devinfo->max_vs_threads - 1; - vs.VertexCacheDisable = false; + + if (GEN_GEN == 9 && devinfo->gt == 4 && + anv_pipeline_has_stage(pipeline, MESA_SHADER_TESS_EVAL)) { + /* On Sky Lake GT4, we have experienced some hangs related to the VS + * cache and tessellation. It is unknown exactly what is happening + * but the Haswell docs for the "VS Reference Count Full Force Miss + * Enable" field of the "Thread Mode" register refer to a HSW bug in + * which the VUE handle reference count would overflow resulting in + * internal reference counting bugs. My (Jason's) best guess is that + * this bug cropped back up on SKL GT4 when we suddenly had more + * threads in play than any previous gen9 hardware. + * + * What we do know for sure is that setting this bit when + * tessellation shaders are in use fixes a GPU hang in Batman: Arkham + * City when playing with DXVK (https://bugs.freedesktop.org/107280). + * Disabling the vertex cache with tessellation shaders should only + * have a minor performance impact as the tessellation shaders are + * likely generating and processing far more geometry than the vertex + * stage. + */ + vs.VertexCacheDisable = true; + } vs.VertexURBEntryReadLength = vs_prog_data->base.urb_read_length; vs.VertexURBEntryReadOffset = 0; -- 2.7.4