From 97e01adfd549c260efd615289938265306d42a05 Mon Sep 17 00:00:00 2001 From: Topi Pohjolainen Date: Wed, 25 Oct 2017 16:50:11 +0300 Subject: [PATCH] intel/compiler/gen9: Pixel shader header only workaround Fixes intermittent GPU hangs on Broxton with an Intel internal test case. There are plenty of similar fragment shaders in piglit that do not use any varyings and any uniforms. According to the documentation special timing is needed between pipeline stages. Apparently we just don't hit that with piglit. Even with the failing test case one doesn't always get the hang. Moreover, according to the error states the hang happens significantly later than the execution of the problematic shader. There are multiple render cycles (primitive submissions) in between. I've also seen error states where the ACTHD points outside the batch. Almost as if the hardware writes somewhere that gets used later on. That would also explain why piglit doesn't suffer from this - most tests kick off one render cycle and any corruption is left unseen. v2 (Ken): Instead of enabling push constants, enable one of the inputs (PSIZ). v3 (Ken, Jason): Use LAYER instead making vulkan emit_3dstate_sbe() happy. Cc: "17.3 17.2" Reviewed-by: Kenneth Graunke Signed-off-by: Topi Pohjolainen --- src/intel/compiler/brw_fs.cpp | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp index 4616529abcf..2dee841c09b 100644 --- a/src/intel/compiler/brw_fs.cpp +++ b/src/intel/compiler/brw_fs.cpp @@ -6166,6 +6166,31 @@ fs_visitor::run_gs() return !failed; } +/* From the SKL PRM, Volume 16, Workarounds: + * + * 0877 3D Pixel Shader Hang possible when pixel shader dispatched with + * only header phases (R0-R2) + * + * WA: Enable a non-header phase (e.g. push constant) when dispatch would + * have been header only. + * + * Instead of enabling push constants one can alternatively enable one of the + * inputs. Here one simply chooses "layer" which shouldn't impose much + * overhead. + */ +static void +gen9_ps_header_only_workaround(struct brw_wm_prog_data *wm_prog_data) +{ + if (wm_prog_data->num_varying_inputs) + return; + + if (wm_prog_data->base.curb_read_length) + return; + + wm_prog_data->urb_setup[VARYING_SLOT_LAYER] = 0; + wm_prog_data->num_varying_inputs = 1; +} + bool fs_visitor::run_fs(bool allow_spilling, bool do_rep_send) { @@ -6229,6 +6254,10 @@ fs_visitor::run_fs(bool allow_spilling, bool do_rep_send) optimize(); assign_curb_setup(); + + if (devinfo->gen >= 9) + gen9_ps_header_only_workaround(wm_prog_data); + assign_urb_setup(); fixup_3src_null_dest(); -- 2.30.2