From: Rob Clark <robclark@freedesktop.org>
Date: Tue, 3 May 2016 16:43:12 +0000 (-0400)
Subject: freedreno/a4xx: deal with VS which do not write position
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1f2bc64f31872f04c27f9aa7a93e63a0091aaabf;p=mesa.git

freedreno/a4xx: deal with VS which do not write position

Fixes $piglit/bin/glsl-1.40-tf-no-position

a3xx may need similar?

Signed-off-by: Rob Clark <robclark@freedesktop.org>
---

diff --git a/src/gallium/drivers/freedreno/a4xx/fd4_program.c b/src/gallium/drivers/freedreno/a4xx/fd4_program.c
index 4396383eef9..9dc4ebbf086 100644
--- a/src/gallium/drivers/freedreno/a4xx/fd4_program.c
+++ b/src/gallium/drivers/freedreno/a4xx/fd4_program.c
@@ -229,6 +229,13 @@ fd4_program_emit(struct fd_ringbuffer *ring, struct fd4_emit *emit,
 	constmode = 1;
 
 	pos_regid = ir3_find_output_regid(s[VS].v, VARYING_SLOT_POS);
+	if (pos_regid == regid(63, 0)) {
+		/* hw dislikes when there is no position output, which can
+		 * happen for transform-feedback vertex shaders.  Just tell
+		 * the hw to use r0.x, with whatever random value is there:
+		 */
+		pos_regid = regid(0, 0);
+	}
 	posz_regid = ir3_find_output_regid(s[FS].v, FRAG_RESULT_DEPTH);
 	psize_regid = ir3_find_output_regid(s[VS].v, VARYING_SLOT_PSIZ);
 	if (s[FS].v->color0_mrt) {