From b9df2251c17e3ce52fa55c81f492591e08c3ee04 Mon Sep 17 00:00:00 2001 From: Anuj Phogat Date: Mon, 24 Oct 2016 16:03:00 -0700 Subject: [PATCH] i965: Fix GPU hang related to multiple render targets and alpha testing This patch should have been the part of commit e592f7df. In a situation when there are multiple render targets with alpha testing enabled, if fragment shader doesn't write to draw buffer zero, it causes the GPU hang on SKL. No GPU hang is seen on HSW. Simulator gives a warning for all gen6+ h/w: "Illegal render target write message length 0xa expected 0xc" This patch fixes the GPU hang as well as the simulator warning with new piglit test fbo-mrt-alphatest-no-buffer-zero-write: https://patchwork.freedesktop.org/patch/118212 No regressions in Jenkins CI system. Cc: "12.0 13.0" Signed-off-by: Anuj Phogat Reviewed-by: Ben Widawsky --- src/mesa/drivers/dri/i965/brw_fs.cpp | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index f839d368f3c..3cdf0bf39f7 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -3673,6 +3673,12 @@ lower_fb_write_logical_send(const fs_builder &bld, fs_inst *inst, */ setup_color_payload(bld, key, &sources[length], src0_alpha, 1); length++; + } else if (key->replicate_alpha && inst->target != 0) { + /* Handle the case when fragment shader doesn't write to draw buffer + * zero. No need to call setup_color_payload() for src0_alpha because + * alpha value will be undefined. + */ + length++; } setup_color_payload(bld, key, &sources[length], color0, components); -- 2.30.2