[Mesa-dev] [PATCH] r600: fix FMASK allocation on r600/700

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

According to NDA docs:
FMASK surfaces are addressed identically a surface with num_samples bits per element, and
log2(num_samples) samples. For example, an FMASK for an 8-sample surface would be addressed
identically to a color surface with 8 bits per element and 3 samples.

Separate the r600 fmask allocation out, and workaround
a bug in the libdrm surface allocation which blocks a 3
sample surface, just round it up to 4.

This fixes hangs with ext_framebuffer_multisample-clip-and-scissor-blit 8 msaa
and destination clipping on my rv635.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/gallium/drivers/radeon/r600_texture.c | 49 +++++++++++++++++++------------
 1 file changed, 30 insertions(+), 19 deletions(-)

diff --git a/src/gallium/drivers/radeon/r600_texture.c b/src/gallium/drivers/radeon/r600_texture.c
index fdf4d76..3ca460a 100644
--- a/src/gallium/drivers/radeon/r600_texture.c
+++ b/src/gallium/drivers/radeon/r600_texture.c
@@ -299,27 +299,38 @@ void r600_texture_get_fmask_info(struct r600_common_screen *rscreen,
 		fmask.flags |= RADEON_SURF_HAS_TILE_MODE_INDEX;
 	}
 
-	switch (nr_samples) {
-	case 2:
-	case 4:
-		fmask.bpe = 1;
-		if (rscreen->chip_class <= CAYMAN) {
-			fmask.bankh = 4;
+	if (rscreen->chip_class <= R700) {
+		/*
+		 * R600/700 -
+		 * FMASK surfaces are addressed identically a surface with num_samples
+		 * bits per element, and log2(num_samples) samples.
+		 */
+		if (nr_samples != 2 && nr_samples != 4 && nr_samples != 8) {
+			R600_ERR("Invalid sample count for FMASK allocation.\n");
+			return;
 		}
-		break;
-	case 8:
-		fmask.bpe = 4;
-		break;
-	default:
-		R600_ERR("Invalid sample count for FMASK allocation.\n");
-		return;
-	}
+		fmask.bpe = nr_samples;
+		fmask.nsamples = log2(nr_samples);
+		/* surface allocator won't do 3 samples */
+		if (fmask.nsamples == 3)
+			fmask.nsamples = 4;
 
-	/* Overallocate FMASK on R600-R700 to fix colorbuffer corruption.
-	 * This can be fixed by writing a separate FMASK allocator specifically
-	 * for R600-R700 asics. */
-	if (rscreen->chip_class <= R700) {
-		fmask.bpe *= 2;
+	} else {
+		switch (nr_samples) {
+		case 2:
+		case 4:
+			fmask.bpe = 1;
+			if (rscreen->chip_class <= CAYMAN) {
+				fmask.bankh = 4;
+			}
+			break;
+		case 8:
+			fmask.bpe = 4;
+			break;
+		default:
+			R600_ERR("Invalid sample count for FMASK allocation.\n");
+			return;
+		}
 	}
 
 	if (rscreen->ws->surface_init(rscreen->ws, &fmask)) {
-- 
2.1.0