Mesa (master): r600g/radeonsi: Reduce or even drop special treatment of persistent mappings

[Michel Dänzer]

Module: Mesa
Branch: master
Commit: 8898fff46cbf62baf4f924b6e8f537a9b1b26fa5
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=8898fff46cbf62baf4f924b6e8f537a9b1b26fa5

Author: Michel Dänzer <michel.daenzer at amd.com>
Date:   Tue Jul 22 18:37:59 2014 +0900

r600g/radeonsi: Reduce or even drop special treatment of persistent mappings

Reviewed-by: Marek Olšák <marek.olsak at amd.com>

---

 src/gallium/drivers/radeon/r600_buffer_common.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/gallium/drivers/radeon/r600_buffer_common.c b/src/gallium/drivers/radeon/r600_buffer_common.c
index 4e6b897..154c33d 100644
--- a/src/gallium/drivers/radeon/r600_buffer_common.c
+++ b/src/gallium/drivers/radeon/r600_buffer_common.c
@@ -127,13 +127,17 @@ bool r600_init_resource(struct r600_common_screen *rscreen,
 		break;
 	}
 
-	/* Use GTT for all persistent mappings, because they are
-	 * always cached and coherent. */
-	if (res->b.b.target == PIPE_BUFFER &&
+	/* Use GTT for all persistent mappings with older kernels, because they
+	 * didn't always flush the HDP cache before CS execution.
+	 *
+	 * Write-combined CPU mappings are fine, the kernel ensures all CPU
+	 * writes finish before the GPU executes a command stream.
+	 */
+	if (rscreen->info.drm_minor < 40 &&
+	    res->b.b.target == PIPE_BUFFER &&
 	    res->b.b.flags & (PIPE_RESOURCE_FLAG_MAP_PERSISTENT |
 			      PIPE_RESOURCE_FLAG_MAP_COHERENT)) {
 		res->domains = RADEON_DOMAIN_GTT;
-		flags = 0;
 	}
 
 	/* Tiled textures are unmappable. Always put them in VRAM. */