From 2ddce3fd0acbdc1be684fb5f919ae3d2e9518aac Mon Sep 17 00:00:00 2001 From: Ian Armstrong Date: Tue, 22 Sep 2009 16:47:52 -0700 Subject: [PATCH] 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 Cc: Krzysztof Helt Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/console/fbcon.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c index 4bee7c2e6313..5a686cea23f4 100644 --- a/drivers/video/console/fbcon.c +++ b/drivers/video/console/fbcon.c @@ -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) { -- 2.20.1