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/*
* drivers/power/process.c - Functions for saving/restoring console.
*
* Originally from swsusp.
*/
#include <linux/vt_kern.h>
#include <linux/kbd_kern.h>
#include <linux/console.h>
#include <linux/module.h>
#include "power.h"
#if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
#define SUSPEND_CONSOLE (MAX_NR_CONSOLES-1)
static int orig_fgconsole, orig_kmsg;
static int disable_vt_switch;
/*
* Normally during a suspend, we allocate a new console and switch to it.
* When we resume, we switch back to the original console. This switch
* can be slow, so on systems where the framebuffer can handle restoration
* of video registers anyways, there's little point in doing the console
* switch. This function allows you to disable it by passing it '0'.
*/
void pm_set_vt_switch(int do_switch)
{
acquire_console_sem();
disable_vt_switch = !do_switch;
release_console_sem();
}
EXPORT_SYMBOL(pm_set_vt_switch);
int pm_prepare_console(void)
{
acquire_console_sem();
if (disable_vt_switch) {
release_console_sem();
return 0;
}
orig_fgconsole = fg_console;
if (vc_allocate(SUSPEND_CONSOLE)) {
/* we can't have a free VC for now. Too bad,
* we don't want to mess the screen for now. */
release_console_sem();
return 1;
}
if (set_console(SUSPEND_CONSOLE)) {
/*
* We're unable to switch to the SUSPEND_CONSOLE.
* Let the calling function know so it can decide
* what to do.
*/
release_console_sem();
return 1;
}
release_console_sem();
if (vt_waitactive(SUSPEND_CONSOLE)) {
pr_debug("Suspend: Can't switch VCs.");
return 1;
}
orig_kmsg = kmsg_redirect;
kmsg_redirect = SUSPEND_CONSOLE;
return 0;
}
void pm_restore_console(void)
{
acquire_console_sem();
if (disable_vt_switch) {
release_console_sem();
return;
}
set_console(orig_fgconsole);
release_console_sem();
if (vt_waitactive(orig_fgconsole)) {
pr_debug("Resume: Can't switch VCs.");
return;
}
kmsg_redirect = orig_kmsg;
}
#endif
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