Commit 2ddce3fd authored Sep 22, 2009 by Ian Armstrong Committed by Linus Torvalds Sep 23, 2009

fbcon: only unbind from console if successfully registered



Attempting to unload a framebuffer module calls unregister_framebuffer()
which in turn gets fbcon to release it.  If fbcon has no framebuffers
linked to a console, it will also unbind itself from the console driver.
However, if fbcon never registered itself as a console driver, the unbind
will fail causing the framebuffer device entry to persist.  In most cases
this failure will result in an oops when attempting to access the now
non-existent device.

This patch ensures that the fbcon unbind request will succeed even if a
bind was never done.  It tracks if a successful bind ever occurred & will
only attempt to unbind if needed.  If there never was a bind, it simply
returns with no error.

Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a690606d

drivers/video/console/fbcon.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -114,6 +114,7 @@ static int last_fb_vc = MAX_NR_CONSOLES - 1;
		static int fbcon_is_default = 1;
		static int fbcon_has_exited;
		static int primary_device = -1;
		static int fbcon_has_console_bind;

		#ifdef CONFIG_FRAMEBUFFER_CONSOLE_DETECT_PRIMARY
		static int map_override;
		@@ -544,6 +545,8 @@ static int fbcon_takeover(int show_logo)
		con2fb_map[i] = -1;
		}
		info_idx = -1;
		} else {
		fbcon_has_console_bind = 1;
		}

		return err;
		@@ -2949,6 +2952,10 @@ static int fbcon_unbind(void)

		ret = unbind_con_driver(&fb_con, first_fb_vc, last_fb_vc,
		fbcon_is_default);

		if (!ret)
		fbcon_has_console_bind = 0;

		return ret;
		}
		#else
		@@ -2962,6 +2969,9 @@ static int fbcon_fb_unbind(int idx)
		{
		int i, new_idx = -1, ret = 0;

		if (!fbcon_has_console_bind)
		return 0;

		for (i = first_fb_vc; i <= last_fb_vc; i++) {
		if (con2fb_map[i] != idx &&
		con2fb_map[i] != -1) {