From cfafca8067c6defbaeb28cb898b7b3f8abdfe20d Mon Sep 17 00:00:00 2001 From: Jesse Barnes Date: Tue, 17 Jul 2007 04:05:33 -0700 Subject: [PATCH] fbdev: fbcon: console unregistration from unregister_framebuffer This allows for proper console unregistration via the VT layer, and updates the FB layer to use it. This makes debugging new console drivers much easier, since you can properly clean them up before unloading. [adaplas] unregister_framebuffer() is typically called as part of the driver's module_exit(). Doing so otherwise will freeze the machine as the VT layer is holding reference counts on fbcon, and fbcon on the driver. With this change, it allows unregister_framebuffer() to be called safely anywhere as needed. Additions from the original: If multiple drivers are used by fbcon, and if one of them unregisters, a driver will take over the consoles vacated by the outgoing one (via set_con2fb_map). Once only the outgoing driver remains, then fbcon will unbind from the VT layer (if CONFIG_HW_CONSOLE_UNBINDING is set to y). It is important that these drivers implement fb_open() and fb_release() just to ensure that no other process is using the driver. Likewise, these drivers _must_ check the return value of unregister_framebuffer(). [akpm@linux-foundation.org: make fbcon_unbind() stub inline] Signed-off-by: Jesse Barnes Signed-off-by: Antonino Daplas Cc: Geert Uytterhoeven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/console/fbcon.c | 42 +++++++++++++++++++++++++++++++++++ drivers/video/fbmem.c | 26 ++++++++++++++++++---- include/linux/fb.h | 2 ++ 3 files changed, 66 insertions(+), 4 deletions(-) diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c index 9b66331020dd..decfdc8eb9cc 100644 --- a/drivers/video/console/fbcon.c +++ b/drivers/video/console/fbcon.c @@ -3003,6 +3003,45 @@ static int fbcon_mode_deleted(struct fb_info *info, return found; } +#ifdef CONFIG_VT_HW_CONSOLE_BINDING +static int fbcon_unbind(void) +{ + int ret; + + ret = unbind_con_driver(&fb_con, first_fb_vc, last_fb_vc, + fbcon_is_default); + return ret; +} +#else +static inline int fbcon_unbind(void) +{ + return -EINVAL; +} +#endif /* CONFIG_VT_HW_CONSOLE_BINDING */ + +static int fbcon_fb_unbind(int idx) +{ + int i, new_idx = -1, ret = 0; + + for (i = first_fb_vc; i <= last_fb_vc; i++) { + if (con2fb_map[i] != idx && + con2fb_map[i] != -1) { + new_idx = i; + break; + } + } + + if (new_idx != -1) { + for (i = first_fb_vc; i <= last_fb_vc; i++) { + if (con2fb_map[i] == idx) + set_con2fb_map(i, new_idx, 0); + } + } else + ret = fbcon_unbind(); + + return ret; +} + static int fbcon_fb_unregistered(struct fb_info *info) { int i, idx = info->node; @@ -3210,6 +3249,9 @@ static int fbcon_event_notify(struct notifier_block *self, mode = event->data; ret = fbcon_mode_deleted(info, mode); break; + case FB_EVENT_FB_UNBIND: + ret = fbcon_fb_unbind(info->node); + break; case FB_EVENT_FB_REGISTERED: ret = fbcon_fb_registered(info); break; diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c index 8d6dbe8b8dd1..7f3a0cca0fd4 100644 --- a/drivers/video/fbmem.c +++ b/drivers/video/fbmem.c @@ -1334,17 +1334,34 @@ register_framebuffer(struct fb_info *fb_info) * * Returns negative errno on error, or zero for success. * + * This function will also notify the framebuffer console + * to release the driver. + * + * This is meant to be called within a driver's module_exit() + * function. If this is called outside module_exit(), ensure + * that the driver implements fb_open() and fb_release() to + * check that no processes are using the device. */ int unregister_framebuffer(struct fb_info *fb_info) { struct fb_event event; - int i; + int i, ret = 0; i = fb_info->node; - if (!registered_fb[i]) - return -EINVAL; + if (!registered_fb[i]) { + ret = -EINVAL; + goto done; + } + + event.info = fb_info; + ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event); + + if (ret) { + ret = -EINVAL; + goto done; + } if (fb_info->pixmap.addr && (fb_info->pixmap.flags & FB_PIXMAP_DEFAULT)) @@ -1356,7 +1373,8 @@ unregister_framebuffer(struct fb_info *fb_info) device_destroy(fb_class, MKDEV(FB_MAJOR, i)); event.info = fb_info; fb_notifier_call_chain(FB_EVENT_FB_UNREGISTERED, &event); - return 0; +done: + return ret; } /** diff --git a/include/linux/fb.h b/include/linux/fb.h index 66226824ab68..8628423c6dd3 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -529,6 +529,8 @@ struct fb_cursor_user { #define FB_EVENT_CONBLANK 0x0C /* Get drawing requirements */ #define FB_EVENT_GET_REQ 0x0D +/* Unbind from the console if possible */ +#define FB_EVENT_FB_UNBIND 0x0E struct fb_event { struct fb_info *info; -- 2.20.1