freedreno/a6xx: Front facing needs UNK3 bit

We need to set UNK3 in GRAS_CNTL and RB_RENDER_CONTROL0 for the value
to be reliably delivered.

Fixes:

  dEQP-GLES3.functional.shaders.builtin_variable.frontfacing

Signed-off-by: Kristian H. Kristensen <hoegsberg@chromium.org>

diff --git a/src/gallium/drivers/freedreno/a6xx/fd6_program.c b/src/gallium/drivers/freedreno/a6xx/fd6_program.c
index 9fde742..470bacf 100644 (file)
--- a/src/gallium/drivers/freedreno/a6xx/fd6_program.c
+++ b/src/gallium/drivers/freedreno/a6xx/fd6_program.c
@@ -549,7 +549,8 @@ setup_stateobj(struct fd_ringbuffer *ring,
                                        A6XX_GRAS_CNTL_XCOORD |
                                        A6XX_GRAS_CNTL_YCOORD |
                                        A6XX_GRAS_CNTL_ZCOORD |
-                                       A6XX_GRAS_CNTL_WCOORD));
+                                       A6XX_GRAS_CNTL_WCOORD) |
+                       COND(s[FS].v->frag_face, A6XX_GRAS_CNTL_UNK3));
 
        OUT_PKT4(ring, REG_A6XX_RB_RENDER_CONTROL0, 2);
        OUT_RING(ring, COND(enable_varyings, A6XX_RB_RENDER_CONTROL0_VARYING |
@@ -559,7 +560,9 @@ setup_stateobj(struct fd_ringbuffer *ring,
                                        A6XX_RB_RENDER_CONTROL0_XCOORD |
                                        A6XX_RB_RENDER_CONTROL0_YCOORD |
                                        A6XX_RB_RENDER_CONTROL0_ZCOORD |
-                                       A6XX_RB_RENDER_CONTROL0_WCOORD));
+                                       A6XX_RB_RENDER_CONTROL0_WCOORD) |
+                       COND(s[FS].v->frag_face, A6XX_RB_RENDER_CONTROL0_UNK3));
+
        OUT_RING(ring, COND(s[FS].v->frag_face, A6XX_RB_RENDER_CONTROL1_FACENESS));
 
        OUT_PKT4(ring, REG_A6XX_SP_FS_OUTPUT_REG(0), 8);