freedreno/a3xx+a4xx: fix for stk binning pass hang

We'd end up in a state where shader uses no inputs, yet num_elements is
greater than zero.  Triggered by a TF vertex shader which did:

  gl_Position = vec4(0.0, 0.0, 0.0, 0.0);

resulting in a binning pass variant with no inputs.

Includes equiv fix in a4xx, even though we don't have binning-pass
enabled yet on a4xx.

Signed-off-by: Rob Clark <[email protected]>

1 files changed, 36 insertions, 9 deletions

diff --git a/src/gallium/drivers/freedreno/a4xx/fd4_emit.c b/src/gallium/drivers/freedreno/a4xx/fd4_emit.c
index 26b58718cd8..5a7b192f79d 100644
--- a/src/gallium/drivers/freedreno/a4xx/fd4_emit.c
+++ b/src/gallium/drivers/freedreno/a4xx/fd4_emit.c
@@ -332,7 +332,10 @@ fd4_emit_vertex_bufs(struct fd_ringbuffer *ring, struct fd4_emit *emit)
 	unsigned instance_regid = regid(63, 0);
 	unsigned vtxcnt_regid = regid(63, 0);
 
+	/* Note that sysvals come *after* normal inputs: */
 	for (i = 0; i < vp->inputs_count; i++) {
+		if (!vp->inputs[i].compmask)
+			continue;
 		if (vp->inputs[i].sysval) {
 			switch(vp->inputs[i].slot) {
 			case SYSTEM_VALUE_BASE_VERTEX:
@@ -351,19 +354,11 @@ fd4_emit_vertex_bufs(struct fd_ringbuffer *ring, struct fd4_emit *emit)
 				unreachable("invalid system value");
 				break;
 			}
-		} else if (i < vtx->vtx->num_elements && vp->inputs[i].compmask) {
+		} else if (i < vtx->vtx->num_elements) {
 			last = i;
 		}
 	}
 
-
-	/* hw doesn't like to be configured for zero vbo's, it seems: */
-	if ((vtx->vtx->num_elements == 0) &&
-			(vertex_regid == regid(63, 0)) &&
-			(instance_regid == regid(63, 0)) &&
-			(vtxcnt_regid == regid(63, 0)))
-		return;
-
 	for (i = 0, j = 0; i <= last; i++) {
 		assert(!vp->inputs[i].sysval);
 		if (vp->inputs[i].compmask) {
@@ -408,6 +403,38 @@ fd4_emit_vertex_bufs(struct fd_ringbuffer *ring, struct fd4_emit *emit)
 		}
 	}
 
+	/* hw doesn't like to be configured for zero vbo's, it seems: */
+	if (last < 0) {
+		/* just recycle the shader bo, we just need to point to *something*
+		 * valid:
+		 */
+		struct fd_bo *dummy_vbo = vp->bo;
+		bool switchnext = (vertex_regid != regid(63, 0)) ||
+				(instance_regid != regid(63, 0)) ||
+				(vtxcnt_regid != regid(63, 0));
+
+		OUT_PKT0(ring, REG_A4XX_VFD_FETCH(0), 4);
+		OUT_RING(ring, A4XX_VFD_FETCH_INSTR_0_FETCHSIZE(0) |
+				A4XX_VFD_FETCH_INSTR_0_BUFSTRIDE(0) |
+				COND(switchnext, A4XX_VFD_FETCH_INSTR_0_SWITCHNEXT));
+		OUT_RELOC(ring, dummy_vbo, 0, 0, 0);
+		OUT_RING(ring, A4XX_VFD_FETCH_INSTR_2_SIZE(1));
+		OUT_RING(ring, A4XX_VFD_FETCH_INSTR_3_STEPRATE(1));
+
+		OUT_PKT0(ring, REG_A4XX_VFD_DECODE_INSTR(0), 1);
+		OUT_RING(ring, A4XX_VFD_DECODE_INSTR_CONSTFILL |
+				A4XX_VFD_DECODE_INSTR_WRITEMASK(0x1) |
+				A4XX_VFD_DECODE_INSTR_FORMAT(VFMT4_8_UNORM) |
+				A4XX_VFD_DECODE_INSTR_SWAP(XYZW) |
+				A4XX_VFD_DECODE_INSTR_REGID(regid(0,0)) |
+				A4XX_VFD_DECODE_INSTR_SHIFTCNT(1) |
+				A4XX_VFD_DECODE_INSTR_LASTCOMPVALID |
+				COND(switchnext, A4XX_VFD_DECODE_INSTR_SWITCHNEXT));
+
+		total_in = 1;
+		j = 1;
+	}
+
 	OUT_PKT0(ring, REG_A4XX_VFD_CONTROL_0, 5);
 	OUT_RING(ring, A4XX_VFD_CONTROL_0_TOTALATTRTOVS(total_in) |
 			0xa0000 | /* XXX */