kernel/power/consoleearlysuspend.c

   1 /* kernel/power/consoleearlysuspend.c
   2  *
   3  * Copyright (C) 2005-2008 Google, Inc.
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <linux/console.h>
  17 #include <linux/earlysuspend.h>
  18 #include <linux/kbd_kern.h>
  19 #include <linux/module.h>
  20 #include <linux/vt_kern.h>
  21 #include <linux/wait.h>
  22
  23 #define EARLY_SUSPEND_CONSOLE   (MAX_NR_CONSOLES-1)
  24
  25 static int orig_fgconsole;
  26 static void console_early_suspend(struct early_suspend *h)
  27 {
  28         acquire_console_sem();
  29         orig_fgconsole = fg_console;
  30         if (vc_allocate(EARLY_SUSPEND_CONSOLE))
  31                 goto err;
  32         if (set_console(EARLY_SUSPEND_CONSOLE))
  33                 goto err;
  34         release_console_sem();
  35
  36         if (vt_waitactive(EARLY_SUSPEND_CONSOLE + 1))
  37                 pr_warning("console_early_suspend: Can't switch VCs.\n");
  38         return;
  39 err:
  40         pr_warning("console_early_suspend: Can't set console\n");
  41         release_console_sem();
  42 }
  43
  44 static void console_late_resume(struct early_suspend *h)
  45 {
  46         int ret;
  47         acquire_console_sem();
  48         ret = set_console(orig_fgconsole);
  49         release_console_sem();
  50         if (ret) {
  51                 pr_warning("console_late_resume: Can't set console.\n");
  52                 return;
  53         }
  54
  55         if (vt_waitactive(orig_fgconsole + 1))
  56                 pr_warning("console_late_resume: Can't switch VCs.\n");
  57 }
  58
  59 static struct early_suspend console_early_suspend_desc = {
  60         .level = EARLY_SUSPEND_LEVEL_STOP_DRAWING,
  61         .suspend = console_early_suspend,
  62         .resume = console_late_resume,
  63 };
  64
  65 static int __init console_early_suspend_init(void)
  66 {
  67         register_early_suspend(&console_early_suspend_desc);
  68         return 0;
  69 }
  70
  71 static void  __exit console_early_suspend_exit(void)
  72 {
  73         unregister_early_suspend(&console_early_suspend_desc);
  74 }
  75
  76 module_init(console_early_suspend_init);
  77 module_exit(console_early_suspend_exit);
  78