Mesa (master): radv: fix issue with multisample positions and interp_var_at_sample.

[Dave Airlie]

Module: Mesa
Branch: master
Commit: b81f1a592b02d3d1928ab232c97675b12cad19fc
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=b81f1a592b02d3d1928ab232c97675b12cad19fc

Author: Dave Airlie <airlied at redhat.com>
Date:   Thu Dec 21 14:03:20 2017 +1000

radv: fix issue with multisample positions and interp_var_at_sample.

This fixes vmfaults seen on vega with:
dEQP-VK.pipeline.multisample_interpolation.sample_interpolate_at_single_sample_.128_128_1.samples_1

These were caused by the don't allocate cmask but it was just accidental.

The actual problem was the shader was trying to get the sample positions from
a buffer, but the buffer was never getting configured to contain them, as the
previous shader never needed them.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
Fixes: 1171b304f3 (radv: overhaul fragment shader sample positions.)
Signed-off-by: Dave Airlie <airlied at redhat.com>

---

 src/amd/vulkan/radv_cmd_buffer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/amd/vulkan/radv_cmd_buffer.c b/src/amd/vulkan/radv_cmd_buffer.c
index a366facd63..6a89d4e568 100644
--- a/src/amd/vulkan/radv_cmd_buffer.c
+++ b/src/amd/vulkan/radv_cmd_buffer.c
@@ -593,7 +593,8 @@ radv_update_multisample_state(struct radv_cmd_buffer *cmd_buffer,
 	radeon_set_context_reg(cmd_buffer->cs, R_028804_DB_EQAA, ms->db_eqaa);
 	radeon_set_context_reg(cmd_buffer->cs, R_028A4C_PA_SC_MODE_CNTL_1, ms->pa_sc_mode_cntl_1);
 
-	if (old_pipeline && num_samples == old_pipeline->graphics.ms.num_samples)
+	if (old_pipeline && num_samples == old_pipeline->graphics.ms.num_samples &&
+	    old_pipeline->shaders[MESA_SHADER_FRAGMENT]->info.info.ps.needs_sample_positions == pipeline->shaders[MESA_SHADER_FRAGMENT]->info.info.ps.needs_sample_positions)
 		return;
 
 	radeon_set_context_reg_seq(cmd_buffer->cs, R_028BDC_PA_SC_LINE_CNTL, 2);