KHR-GL43.compute_shader.resource-texture fails with MCS fast clears disabled
Submitted by Kenneth Graunke
Assigned to Intel 3D Bugs Mailing List
Created attachment 142859 Patch to narrow the CTS test to a smaller reproducer
I believe I've found a bug with MCS and slow clears.
If I disable fast clears (hack brw_blorp.c to add "can_fast_clear = false"), then KHR-GL43.compute_shader.resource-texture fails on my Kabylake system. The test clears a 4x MSAA 4x16 R32G32B32A32_FLOAT texture, which is using the CMS layout. Disabling CMS/MCS also fixes it. (There are actually two, one is a single slice, the other is a 2-slice array texture. Both are broken.) It then samples the textures with a compute shader.
Fast clears ought to be optional - I think they may be masking a bug.
The attached patch to the CTS test narrows it down to a much smaller test case.
This is fairly outside of my expertise, so I'd appreciate it if some MCS experts could take a look (without ruining your holiday plans)...thanks!
Patch 142859, "Patch to narrow the CTS test to a smaller reproducer":