Mesa (master): r600g: add workaround for buggy hw scissor on eg/cayman.

[Dave Airlie]

Module: Mesa
Branch: master
Commit: 868c04205c3859a816593595aa513ee603f736ad
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=868c04205c3859a816593595aa513ee603f736ad

Author: Dave Airlie <airlied at redhat.com>
Date:   Wed May 25 09:25:03 2011 +1000

r600g: add workaround for buggy hw scissor on eg/cayman.

This is ported from the same fix to the DDX.

Signed-off-by: Dave Airlie <airlied at redhat.com>

---

 src/gallium/drivers/r600/evergreen_state.c |   15 ++++++++++++++-
 1 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/src/gallium/drivers/r600/evergreen_state.c b/src/gallium/drivers/r600/evergreen_state.c
index dcb2806..adf9366 100644
--- a/src/gallium/drivers/r600/evergreen_state.c
+++ b/src/gallium/drivers/r600/evergreen_state.c
@@ -861,6 +861,7 @@ static void evergreen_set_framebuffer_state(struct pipe_context *ctx,
 	struct r600_pipe_state *rstate = CALLOC_STRUCT(r600_pipe_state);
 	u32 shader_mask, tl, br, target_mask;
 	enum radeon_family family;
+	int scissor_width, scissor_height;
 
 	if (rstate == NULL)
 		return;
@@ -891,8 +892,20 @@ static void evergreen_set_framebuffer_state(struct pipe_context *ctx,
 		target_mask ^= 0xf << (i * 4);
 		shader_mask |= 0xf << (i * 4);
 	}
+	scissor_width = state->width;
+	scissor_height = state->height;
+	/* EG hw workaround */
+	if (scissor_width == 0)
+		scissor_width = 1;
+	if (scissor_height == 0)
+		scissor_height = 1;
+	/* cayman hw workaround */
+	if (family == CHIP_CAYMAN) {
+		if (scissor_width == 1 && scissor_height == 1)
+			scissor_width = 2;
+	}
 	tl = S_028240_TL_X(0) | S_028240_TL_Y(0);
-	br = S_028244_BR_X(state->width) | S_028244_BR_Y(state->height);
+	br = S_028244_BR_X(scissor_width) | S_028244_BR_Y(scissor_height);
 
 	r600_pipe_state_add_reg(rstate,
 				R_028240_PA_SC_GENERIC_SCISSOR_TL, tl,