DRI2: Don't fault on NULL DrawBuffer

It is possible for ctx->DrawBuffer to be NULL, so don't fault when
that happens.  This change is not being committed to master because it
doesn't appear to be necessary there.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Cherry picked from mesa_7_4_branch, commit 49e0c74ddd91900fc4effb6d305d56e0563b456d

diff --git a/src/mesa/drivers/dri/intel/intel_buffers.c b/src/mesa/drivers/dri/intel/intel_buffers.c
index f1249f7..90964df 100644 (file)
--- a/src/mesa/drivers/dri/intel/intel_buffers.c
+++ b/src/mesa/drivers/dri/intel/intel_buffers.c
@@ -321,7 +321,7 @@ intel_draw_buffer(GLcontext * ctx, struct gl_framebuffer *fb)
 static void
 intelDrawBuffer(GLcontext * ctx, GLenum mode)
 {
-   if (ctx->DrawBuffer->Name == 0) {
+   if ((ctx->DrawBuffer != NULL) && (ctx->DrawBuffer->Name == 0)) {
       struct intel_context *const intel = intel_context(ctx);
 
       intel->is_front_buffer_rendering = (mode == GL_FRONT_LEFT);