kernel/power/console.c

   1 /*
   2  * drivers/power/process.c - Functions for saving/restoring console.
   3  *
   4  * Originally from swsusp.
   5  */
   6
   7 #include <linux/vt_kern.h>
   8 #include <linux/kbd_kern.h>
   9 #include <linux/console.h>
  10 #include "power.h"
  11
  12 static int new_loglevel = 10;
  13 static int orig_loglevel;
  14 static int orig_fgconsole, orig_kmsg;
  15
  16 int pm_prepare_console(void)
  17 {
  18         orig_loglevel = console_loglevel;
  19         console_loglevel = new_loglevel;
  20
  21 #ifdef SUSPEND_CONSOLE
  22         acquire_console_sem();
  23
  24         orig_fgconsole = fg_console;
  25
  26         if (vc_allocate(SUSPEND_CONSOLE)) {
  27           /* we can't have a free VC for now. Too bad,
  28            * we don't want to mess the screen for now. */
  29                 release_console_sem();
  30                 return 1;
  31         }
  32
  33         set_console(SUSPEND_CONSOLE);
  34         release_console_sem();
  35
  36         if (vt_waitactive(SUSPEND_CONSOLE)) {
  37                 pr_debug("Suspend: Can't switch VCs.");
  38                 return 1;
  39         }
  40         orig_kmsg = kmsg_redirect;
  41         kmsg_redirect = SUSPEND_CONSOLE;
  42 #endif
  43         return 0;
  44 }
  45
  46 void pm_restore_console(void)
  47 {
  48         console_loglevel = orig_loglevel;
  49 #ifdef SUSPEND_CONSOLE
  50         acquire_console_sem();
  51         set_console(orig_fgconsole);
  52         release_console_sem();
  53 #endif
  54         return;
  55 }