DRI2: more informative messages for /var/log/Xorg.0.log

Explain that AIGLX is normally expected to fail and the users should
not really worry about it. Also provide a warning in the case if the
driver has been compiled without libUMP support (it could be that
the user actually wanted 3D acceleration, but just has not installed
all the needed dependencies).
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

src/fbdev.c

@@ -977,17 +977,29 @@ FBDevScreenInit(SCREEN_INIT_ARGS_DECL)
 	    fPtr->SunxiMaliDRI2_private = SunxiMaliDRI2_Init(pScreen,
 		xf86ReturnOptValBool(fPtr->Options, OPTION_DRI2_OVERLAY, TRUE));
 
-	    if (fPtr->SunxiMaliDRI2_private)
+	    if (fPtr->SunxiMaliDRI2_private) {
 		xf86DrvMsg(pScrn->scrnIndex, X_INFO,
 		           "using DRI2 integration for Mali GPU (UMP buffers)\n");
-	    else
+		xf86DrvMsg(pScrn->scrnIndex, X_INFO,
+		           "Mali binary drivers can only accelerate EGL/GLES\n");
+		xf86DrvMsg(pScrn->scrnIndex, X_INFO,
+		           "so AIGLX/GLX is expected to fail or fallback to software\n");
+		xf86DrvMsg(pScrn->scrnIndex, X_INFO,
+	    }
+	    else {
 		xf86DrvMsg(pScrn->scrnIndex, X_INFO,
 		           "failed to enable DRI2 integration for Mali GPU\n");
+	    }
 	}
 	else {
 	    xf86DrvMsg(pScrn->scrnIndex, X_INFO,
 	               "DRI2 integration for Mali GPU is disabled in xorg.conf\n");
 	}
+#else
+	xf86DrvMsg(pScrn->scrnIndex, X_INFO,
+	           "no 3D acceleration because the driver has been compiled without libUMP\n");
+	xf86DrvMsg(pScrn->scrnIndex, X_INFO,
+	           "if this is wrong and needs to be fixed, please check ./configure log\n");
 #endif
 
 	TRACE_EXIT("FBDevScreenInit");