mirror of https://gitee.com/openkylin/linux.git
fbdev: fix info->lock deadlock in fbcon_event_notify()
fb_notifier_call_chain() is called with info->lock held, i.e. in do_fb_ioctl() => FBIOPUT_VSCREENINFO => fb_set_var() and the some notifier callbacks, like fbcon_event_notify(), try to re-acquire info->lock again. Remove the lock/unlock_fb_info() in all the framebuffer notifier callbacks' and be sure to always call fb_notifier_call_chain() with info->lock held. Reported-by: Pavel Roskin <proski@gnu.org> Reported-by: Eric Miao <eric.y.miao@gmail.com> Signed-off-by: Andrea Righi <righi.andrea@gmail.com> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b52bb3712a
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513adb5868
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@ -35,8 +35,6 @@ static int fb_notifier_callback(struct notifier_block *self,
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return 0;
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bd = container_of(self, struct backlight_device, fb_notif);
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if (!lock_fb_info(evdata->info))
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return -ENODEV;
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mutex_lock(&bd->ops_lock);
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if (bd->ops)
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if (!bd->ops->check_fb ||
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@ -49,7 +47,6 @@ static int fb_notifier_callback(struct notifier_block *self,
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backlight_update_status(bd);
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}
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mutex_unlock(&bd->ops_lock);
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unlock_fb_info(evdata->info);
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return 0;
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}
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@ -40,8 +40,6 @@ static int fb_notifier_callback(struct notifier_block *self,
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if (!ld->ops)
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return 0;
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if (!lock_fb_info(evdata->info))
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return -ENODEV;
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mutex_lock(&ld->ops_lock);
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if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) {
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if (event == FB_EVENT_BLANK) {
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@ -53,7 +51,6 @@ static int fb_notifier_callback(struct notifier_block *self,
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}
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}
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mutex_unlock(&ld->ops_lock);
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unlock_fb_info(evdata->info);
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return 0;
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}
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@ -2263,9 +2263,12 @@ static void fbcon_generic_blank(struct vc_data *vc, struct fb_info *info,
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}
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if (!lock_fb_info(info))
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return;
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event.info = info;
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event.data = ␣
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fb_notifier_call_chain(FB_EVENT_CONBLANK, &event);
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unlock_fb_info(info);
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}
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static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch)
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@ -2956,8 +2959,6 @@ static int fbcon_fb_unregistered(struct fb_info *info)
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{
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int i, idx;
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if (!lock_fb_info(info))
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return -ENODEV;
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idx = info->node;
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for (i = first_fb_vc; i <= last_fb_vc; i++) {
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if (con2fb_map[i] == idx)
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@ -2985,8 +2986,6 @@ static int fbcon_fb_unregistered(struct fb_info *info)
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if (primary_device == idx)
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primary_device = -1;
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unlock_fb_info(info);
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if (!num_registered_fb)
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unregister_con_driver(&fb_con);
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@ -3027,11 +3026,8 @@ static int fbcon_fb_registered(struct fb_info *info)
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{
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int ret = 0, i, idx;
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if (!lock_fb_info(info))
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return -ENODEV;
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idx = info->node;
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fbcon_select_primary(info);
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unlock_fb_info(info);
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if (info_idx == -1) {
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for (i = first_fb_vc; i <= last_fb_vc; i++) {
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@ -3152,53 +3148,23 @@ static int fbcon_event_notify(struct notifier_block *self,
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switch(action) {
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case FB_EVENT_SUSPEND:
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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fbcon_suspended(info);
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unlock_fb_info(info);
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break;
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case FB_EVENT_RESUME:
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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fbcon_resumed(info);
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unlock_fb_info(info);
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break;
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case FB_EVENT_MODE_CHANGE:
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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fbcon_modechanged(info);
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unlock_fb_info(info);
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break;
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case FB_EVENT_MODE_CHANGE_ALL:
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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fbcon_set_all_vcs(info);
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unlock_fb_info(info);
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break;
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case FB_EVENT_MODE_DELETE:
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mode = event->data;
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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ret = fbcon_mode_deleted(info, mode);
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unlock_fb_info(info);
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break;
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case FB_EVENT_FB_UNBIND:
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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idx = info->node;
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unlock_fb_info(info);
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ret = fbcon_fb_unbind(idx);
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break;
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case FB_EVENT_FB_REGISTERED:
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@ -3217,29 +3183,14 @@ static int fbcon_event_notify(struct notifier_block *self,
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con2fb->framebuffer = con2fb_map[con2fb->console - 1];
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break;
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case FB_EVENT_BLANK:
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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fbcon_fb_blanked(info, *(int *)event->data);
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unlock_fb_info(info);
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break;
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case FB_EVENT_NEW_MODELIST:
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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fbcon_new_modelist(info);
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unlock_fb_info(info);
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break;
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case FB_EVENT_GET_REQ:
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caps = event->data;
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if (!lock_fb_info(info)) {
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ret = -ENODEV;
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goto done;
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}
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fbcon_get_requirement(info, caps);
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unlock_fb_info(info);
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break;
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}
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done:
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@ -1097,8 +1097,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
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return -EINVAL;
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con2fb.framebuffer = -1;
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event.data = &con2fb;
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if (!lock_fb_info(info))
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return -ENODEV;
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event.info = info;
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fb_notifier_call_chain(FB_EVENT_GET_CONSOLE_MAP, &event);
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unlock_fb_info(info);
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ret = copy_to_user(argp, &con2fb, sizeof(con2fb)) ? -EFAULT : 0;
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break;
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case FBIOPUT_CON2FBMAP:
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@ -1115,8 +1118,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
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break;
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}
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event.data = &con2fb;
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if (!lock_fb_info(info))
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return -ENODEV;
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event.info = info;
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ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP, &event);
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unlock_fb_info(info);
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break;
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case FBIOBLANK:
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if (!lock_fb_info(info))
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@ -1521,7 +1527,10 @@ register_framebuffer(struct fb_info *fb_info)
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registered_fb[i] = fb_info;
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event.info = fb_info;
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if (!lock_fb_info(fb_info))
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return -ENODEV;
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fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
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unlock_fb_info(fb_info);
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return 0;
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}
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@ -1555,8 +1564,12 @@ unregister_framebuffer(struct fb_info *fb_info)
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goto done;
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}
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if (!lock_fb_info(fb_info))
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return -ENODEV;
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event.info = fb_info;
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ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event);
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unlock_fb_info(fb_info);
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if (ret) {
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ret = -EINVAL;
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@ -1590,6 +1603,8 @@ void fb_set_suspend(struct fb_info *info, int state)
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{
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struct fb_event event;
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if (!lock_fb_info(info))
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return;
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event.info = info;
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if (state) {
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fb_notifier_call_chain(FB_EVENT_SUSPEND, &event);
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@ -1598,6 +1613,7 @@ void fb_set_suspend(struct fb_info *info, int state)
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info->state = FBINFO_STATE_RUNNING;
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fb_notifier_call_chain(FB_EVENT_RESUME, &event);
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}
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unlock_fb_info(info);
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}
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/**
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@ -1667,8 +1683,11 @@ int fb_new_modelist(struct fb_info *info)
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err = 1;
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if (!list_empty(&info->modelist)) {
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if (!lock_fb_info(info))
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return -ENODEV;
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event.info = info;
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err = fb_notifier_call_chain(FB_EVENT_NEW_MODELIST, &event);
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unlock_fb_info(info);
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}
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return err;
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