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" <mesa-sta...@lists.freedesktop.org> Signed-off-by: Anuj Phogat <anuj.pho...@gmail.com> --- 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 921cc00..afb1057 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); -- 2.5.5 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
