diff --git a/glx/glxcmds.c b/glx/glxcmds.c
index af52672f1..33954ee64 100644
--- a/glx/glxcmds.c
+++ b/glx/glxcmds.c
@@ -146,6 +146,8 @@ __glXContextDestroy(__GLXcontext *context)
 	    __glXUnrefDrawable(context->drawPriv);
 	if (context->readPriv)
 	    __glXUnrefDrawable(context->readPriv);
+	context->drawPriv = NULL;
+	context->readPriv = NULL;
     }
     __glXFlushContextCache();
 }
@@ -621,6 +623,8 @@ DoMakeCurrent(__GLXclientState *cl,
 		__glXUnrefDrawable(prevglxc->drawPriv);
 	    if (prevglxc->readPriv)
 		__glXUnrefDrawable(prevglxc->readPriv);
+	    prevglxc->drawPriv = NULL;
+	    prevglxc->readPriv = NULL;
 	}
     }
 	
diff --git a/hw/xfree86/modes/xf86Crtc.c b/hw/xfree86/modes/xf86Crtc.c
index 30308ade4..40352b4fd 100644
--- a/hw/xfree86/modes/xf86Crtc.c
+++ b/hw/xfree86/modes/xf86Crtc.c
@@ -3159,9 +3159,6 @@ xf86_crtc_supports_gamma(ScrnInfoPtr pScrn)
 	xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(pScrn);
 	xf86CrtcPtr crtc;
 
-	if (!xf86_config)
-	    return FALSE;
-
 	if (xf86_config->num_crtc == 0)
 	    return FALSE;
 	crtc = xf86_config->crtc[0];