Mesa (master): intel: make intel_flush_front safe to call during initial MakeCurrent

[Paul Berry]

Module: Mesa
Branch: master
Commit: 03cc31031315059a80d12485a402ea2a8731dc8a
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=03cc31031315059a80d12485a402ea2a8731dc8a

Author: Paul Berry <stereotype441 at gmail.com>
Date:   Thu May 30 07:08:07 2013 -0700

intel: make intel_flush_front safe to call during initial MakeCurrent

The patch that follows will fix a bug that prevents
intel_flush_front() from being called often enough.  In doing so, it
will create a situation where intel_flush_front() is called during the
initial call to glXMakeCurrent().  In this circumstance,
ctx->DrawBuffer hasn't been initialized yet and is NULL.  Fortunately,
intel->front_buffer_dirty is false, so intel_flush_front() doesn't
actually need to do anything.  To avoid a segfault, swap the order of
terms in intel_flush_front()'s if statement.

Reviewed-by: Chad Versace <chad.versace at linux.intel.com>
Reviewed-by: Anuj Phogat <anuj.phogat at gmail.com>

---

 src/mesa/drivers/dri/intel/intel_context.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/mesa/drivers/dri/intel/intel_context.c b/src/mesa/drivers/dri/intel/intel_context.c
index 8c88b3c..54d0a69 100644
--- a/src/mesa/drivers/dri/intel/intel_context.c
+++ b/src/mesa/drivers/dri/intel/intel_context.c
@@ -132,7 +132,7 @@ intel_flush_front(struct gl_context *ctx)
     __DRIdrawable *driDrawable = driContext->driDrawablePriv;
     __DRIscreen *const screen = intel->intelScreen->driScrnPriv;
 
-    if (_mesa_is_winsys_fbo(ctx->DrawBuffer) && intel->front_buffer_dirty) {
+    if (intel->front_buffer_dirty && _mesa_is_winsys_fbo(ctx->DrawBuffer)) {
       if (screen->dri2.loader->flushFrontBuffer != NULL &&
           driDrawable &&
           driDrawable->loaderPrivate) {