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 #ifdef SUSPEND_CONSOLE
  15 static int orig_fgconsole, orig_kmsg;
  16 #endif
  17
  18 int pm_prepare_console(void)
  19 {
  20         orig_loglevel = console_loglevel;
  21         console_loglevel = new_loglevel;
  22
  23 #ifdef SUSPEND_CONSOLE
  24         acquire_console_sem();
  25
  26         orig_fgconsole = fg_console;
  27
  28         if (vc_allocate(SUSPEND_CONSOLE)) {
  29           /* we can't have a free VC for now. Too bad,
  30            * we don't want to mess the screen for now. */
  31                 release_console_sem();
  32                 return 1;
  33         }
  34
  35         set_console(SUSPEND_CONSOLE);
  36         release_console_sem();
  37
  38         if (vt_waitactive(SUSPEND_CONSOLE)) {
  39                 pr_debug("Suspend: Can't switch VCs.");
  40                 return 1;
  41         }
  42         orig_kmsg = kmsg_redirect;
  43         kmsg_redirect = SUSPEND_CONSOLE;
  44 #endif
  45         return 0;
  46 }
  47
  48 void pm_restore_console(void)
  49 {
  50         console_loglevel = orig_loglevel;
  51 #ifdef SUSPEND_CONSOLE
  52         acquire_console_sem();
  53         set_console(orig_fgconsole);
  54         release_console_sem();
  55         kmsg_redirect = orig_kmsg;
  56 #endif
  57         return;
  58 }