From c09e2143c7e315fc5cbd302237d6a9c35c6f8a77 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel@tungstengraphics.com>
Date: Wed, 17 Oct 2007 18:26:31 +0200
Subject: [PATCH] i915tex: Don't emit 'empty' blit rectangles.

The hardware seems to interpret them differently and produce unexpected
results...
---
 src/mesa/drivers/dri/i915tex/intel_blit.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/mesa/drivers/dri/i915tex/intel_blit.c b/src/mesa/drivers/dri/i915tex/intel_blit.c
index dbe4ba2ac5e..a0601515c16 100644
--- a/src/mesa/drivers/dri/i915tex/intel_blit.c
+++ b/src/mesa/drivers/dri/i915tex/intel_blit.c
@@ -409,6 +409,9 @@ intelClearWithBlit(GLcontext * ctx, GLbitfield mask)
             b = *box;
          }
 
+         if (b.x1 >= b.x2 || b.y1 >= b.y2)
+            continue;
+
          if (0)
             _mesa_printf("clear %d,%d..%d,%d, mask %x\n",
                          b.x1, b.y1, b.x2, b.y2, mask);