From: Francisco Jerez <currojerez@riseup.net>
Date: Tue, 22 Sep 2009 23:47:53 +0000 (-0700)
Subject: vgacon: prevent vgacon_deinit from touching the hardware for inactive consoles.
X-Git-Tag: v2.6.32-rc1~186
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f0c7d2b72ad1a694c0c886a14cc708841181e9bd;p=platform%2Fkernel%2Flinux-stable.git

vgacon: prevent vgacon_deinit from touching the hardware for inactive consoles.

fbcon makes the (reasonable) assumption that it only needs to program the
hardware once, when fbcon_init() is called for the foreground console.

This doesn't always play well with vgacon because vgacon_deinit() is only
doing its job when the last console it owns is closed (when switching from
vgacon to fbcon, that's usually *after* fbcon_init() has set the new
mode).

Depending on the hardware this can cause the wrong framebuffer location to
be scanned out (e.g.  reproduced on nv05 with the nouveau framebuffer
driver).

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 74e96cf..da55cca 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -589,12 +589,14 @@ static void vgacon_init(struct vc_data *c, int init)
 
 static void vgacon_deinit(struct vc_data *c)
 {
-	/* When closing the last console, reset video origin */
-	if (!--vgacon_uni_pagedir[1]) {
+	/* When closing the active console, reset video origin */
+	if (CON_IS_VISIBLE(c)) {
 		c->vc_visible_origin = vga_vram_base;
 		vga_set_mem_top(c);
-		con_free_unimap(c);
 	}
+
+	if (!--vgacon_uni_pagedir[1])
+		con_free_unimap(c);
 	c->vc_uni_pagedir_loc = &c->vc_uni_pagedir;
 	con_set_default_unimap(c);
 }