Mesa (master): freedreno/a4xx: rasterizer_discard support

[Rob Clark]

Module: Mesa
Branch: master
Commit: 46e9bbc9182243c4599aa7dc811d404a18833cd7
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=46e9bbc9182243c4599aa7dc811d404a18833cd7

Author: Rob Clark <robclark at freedesktop.org>
Date:   Tue Apr 12 14:51:33 2016 -0400

freedreno/a4xx: rasterizer_discard support

This one is slightly annoying, since trying to write RBRC from draw
would clobber values set in the tiling/gmem code.  We could do command-
stream patching for RBRC, as is done on a3xx.  Although since it seems
to be a rarely used feature, it is easier just to do RMW to set/clear
the bit.

Fixes dEQP-GLES3.functional.rasterizer_discard.basic.write_depth_triangles
and related tests.

a3xx still needs the same feature, although there it probably makes more
sense to take advantage of the existing cmdstream patching which is
required for RBRC for other reasons.

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

---

 src/gallium/drivers/freedreno/a4xx/fd4_draw.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/gallium/drivers/freedreno/a4xx/fd4_draw.c b/src/gallium/drivers/freedreno/a4xx/fd4_draw.c
index c34f944..e874d22 100644
--- a/src/gallium/drivers/freedreno/a4xx/fd4_draw.c
+++ b/src/gallium/drivers/freedreno/a4xx/fd4_draw.c
@@ -157,7 +157,24 @@ fd4_draw_vbo(struct fd_context *ctx, const struct pipe_draw_info *info)
 	emit.dirty = dirty;
 	emit.vp = NULL;   /* we changed key so need to refetch vp */
 	emit.fp = NULL;
+
+	if (ctx->rasterizer->rasterizer_discard) {
+		fd_wfi(ctx, ctx->ring);
+		OUT_PKT3(ctx->ring, CP_REG_RMW, 3);
+		OUT_RING(ctx->ring, REG_A4XX_RB_RENDER_CONTROL);
+		OUT_RING(ctx->ring, ~A4XX_RB_RENDER_CONTROL_DISABLE_COLOR_PIPE);
+		OUT_RING(ctx->ring, A4XX_RB_RENDER_CONTROL_DISABLE_COLOR_PIPE);
+	}
+
 	draw_impl(ctx, ctx->ring, &emit);
+
+	if (ctx->rasterizer->rasterizer_discard) {
+		fd_wfi(ctx, ctx->ring);
+		OUT_PKT3(ctx->ring, CP_REG_RMW, 3);
+		OUT_RING(ctx->ring, REG_A4XX_RB_RENDER_CONTROL);
+		OUT_RING(ctx->ring, ~A4XX_RB_RENDER_CONTROL_DISABLE_COLOR_PIPE);
+		OUT_RING(ctx->ring, 0);
+	}
 }
 
 /* clear operations ignore viewport state, so we need to reset it