i915: Fix off-by-one for drawing rectangle.

The drawing rectangle is given in *inclusive* pixel values, so the range
is only [0,2047]. Hence when rendering to a 2048 wide target, such as an
extended desktop, we would issue an illegal instruction zeroing the draw
area.

Fixes:

  Bug 27408: Primary and Secondary display blanks in extended
             desktop mode with Compiz enabled
  https://bugs.freedesktop.org/show_bug.cgi?id=27408

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/src/mesa/drivers/dri/i915/i915_vtbl.c b/src/mesa/drivers/dri/i915/i915_vtbl.c
index 974ab3ec14a5c81e87702a327e19028c7646e4f0..b2f9b90abd84136554690f1009387d531a3653fb 100644 (file)
--- a/src/mesa/drivers/dri/i915/i915_vtbl.c
+++ b/src/mesa/drivers/dri/i915/i915_vtbl.c
@@ -627,8 +627,8 @@ i915_set_draw_region(struct intel_context *intel,
    state->Buffer[I915_DESTREG_DRAWRECT2] = 0;
    state->Buffer[I915_DESTREG_DRAWRECT3] = (draw_y << 16) | draw_x;
    state->Buffer[I915_DESTREG_DRAWRECT4] =
-      ((ctx->DrawBuffer->Width + draw_x) & 0xffff) |
-      ((ctx->DrawBuffer->Height + draw_y) << 16);
+      ((ctx->DrawBuffer->Width + draw_x - 1) & 0xffff) |
+      ((ctx->DrawBuffer->Height + draw_y - 1) << 16);
    state->Buffer[I915_DESTREG_DRAWRECT5] = (draw_y << 16) | draw_x;
 
    I915_STATECHANGE(i915, I915_UPLOAD_BUFFERS);