From 34d0aae6723cb114c79450221667fb55af7f2eae Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@gmx.de>
Date: Thu, 3 Jan 2013 15:33:51 +0100
Subject: [PATCH] devvga: check if screen is setup before accepting hwgc vgactl

---
 sys/src/9/pc/devvga.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sys/src/9/pc/devvga.c b/sys/src/9/pc/devvga.c
index bdc59f11d..14df25b89 100644
--- a/sys/src/9/pc/devvga.c
+++ b/sys/src/9/pc/devvga.c
@@ -257,6 +257,9 @@ vgactl(Cmdbuf *cb)
 	ct = lookupcmd(cb, vgactlmsg, nelem(vgactlmsg));
 	switch(ct->index){
 	case CMhwgc:
+		if(scr->gscreen == nil)
+			error("hwgc: no gscreen");
+
 		if(strcmp(cb->f[1], "off") == 0){
 			lock(&cursor);
 			if(scr->cur){