[Mesa-dev] [PATCH] gallium/radeon: add a debug flag not to use write combining

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

---
 src/gallium/drivers/radeon/r600_buffer_common.c | 6 ++++--
 src/gallium/drivers/radeon/r600_pipe_common.c   | 1 +
 src/gallium/drivers/radeon/r600_pipe_common.h   | 1 +
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/radeon/r600_buffer_common.c b/src/gallium/drivers/radeon/r600_buffer_common.c
index fc5f6c2..d5ee188 100644
--- a/src/gallium/drivers/radeon/r600_buffer_common.c
+++ b/src/gallium/drivers/radeon/r600_buffer_common.c
@@ -111,7 +111,8 @@ bool r600_init_resource(struct r600_common_screen *rscreen,
 
 	switch (res->b.b.usage) {
 	case PIPE_USAGE_STREAM:
-		flags = RADEON_FLAG_GTT_WC;
+		if (!(rscreen->debug_flags & DBG_NO_WC))
+			flags = RADEON_FLAG_GTT_WC;
 		/* fall through */
 	case PIPE_USAGE_STAGING:
 		/* Transfers are likely to occur more often with these resources. */
@@ -133,7 +134,8 @@ bool r600_init_resource(struct r600_common_screen *rscreen,
 	default:
 		/* Not listing GTT here improves performance in some apps. */
 		res->domains = RADEON_DOMAIN_VRAM;
-		flags |= RADEON_FLAG_GTT_WC;
+		if (!(rscreen->debug_flags & DBG_NO_WC))
+			flags |= RADEON_FLAG_GTT_WC;
 		break;
 	}
 
diff --git a/src/gallium/drivers/radeon/r600_pipe_common.c b/src/gallium/drivers/radeon/r600_pipe_common.c
index 79b4b54..b12992d 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.c
+++ b/src/gallium/drivers/radeon/r600_pipe_common.c
@@ -351,6 +351,7 @@ static const struct debug_named_value common_debug_options[] = {
 	{ "switch_on_eop", DBG_SWITCH_ON_EOP, "Program WD/IA to switch on end-of-packet." },
 	{ "forcedma", DBG_FORCE_DMA, "Use asynchronous DMA for all operations when possible." },
 	{ "precompile", DBG_PRECOMPILE, "Compile one shader variant at shader creation." },
+	{ "nowc", DBG_NO_WC, "Disable GTT write combining" },
 
 	DEBUG_NAMED_VALUE_END /* must be last */
 };
diff --git a/src/gallium/drivers/radeon/r600_pipe_common.h b/src/gallium/drivers/radeon/r600_pipe_common.h
index fbd2a21..01c4bd3 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.h
+++ b/src/gallium/drivers/radeon/r600_pipe_common.h
@@ -95,6 +95,7 @@
 #define DBG_FORCE_DMA		(1llu << 38)
 #define DBG_PRECOMPILE		(1llu << 39)
 #define DBG_INFO		(1llu << 40)
+#define DBG_NO_WC		(1llu << 41)
 
 #define R600_MAP_BUFFER_ALIGNMENT 64
 
-- 
2.1.4