150 lines
3.4 KiB
C
150 lines
3.4 KiB
C
/*
|
|
* Functions for saving/restoring console.
|
|
*
|
|
* Originally from swsusp.
|
|
*/
|
|
|
|
#include <linux/console.h>
|
|
#include <linux/vt_kern.h>
|
|
#include <linux/kbd_kern.h>
|
|
#include <linux/vt.h>
|
|
#include <linux/module.h>
|
|
#include "power.h"
|
|
|
|
#define SUSPEND_CONSOLE (MAX_NR_CONSOLES-1)
|
|
|
|
static int orig_fgconsole, orig_kmsg;
|
|
|
|
static DEFINE_MUTEX(vt_switch_mutex);
|
|
|
|
struct pm_vt_switch {
|
|
struct list_head head;
|
|
struct device *dev;
|
|
bool required;
|
|
};
|
|
|
|
static LIST_HEAD(pm_vt_switch_list);
|
|
|
|
|
|
/**
|
|
* pm_vt_switch_required - indicate VT switch at suspend requirements
|
|
* @dev: device
|
|
* @required: if true, caller needs VT switch at suspend/resume time
|
|
*
|
|
* The different console drivers may or may not require VT switches across
|
|
* suspend/resume, depending on how they handle restoring video state and
|
|
* what may be running.
|
|
*
|
|
* Drivers can indicate support for switchless suspend/resume, which can
|
|
* save time and flicker, by using this routine and passing 'false' as
|
|
* the argument. If any loaded driver needs VT switching, or the
|
|
* no_console_suspend argument has been passed on the command line, VT
|
|
* switches will occur.
|
|
*/
|
|
void pm_vt_switch_required(struct device *dev, bool required)
|
|
{
|
|
struct pm_vt_switch *entry, *tmp;
|
|
|
|
mutex_lock(&vt_switch_mutex);
|
|
list_for_each_entry(tmp, &pm_vt_switch_list, head) {
|
|
if (tmp->dev == dev) {
|
|
/* already registered, update requirement */
|
|
tmp->required = required;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
|
|
if (!entry)
|
|
goto out;
|
|
|
|
entry->required = required;
|
|
entry->dev = dev;
|
|
|
|
list_add(&entry->head, &pm_vt_switch_list);
|
|
out:
|
|
mutex_unlock(&vt_switch_mutex);
|
|
}
|
|
EXPORT_SYMBOL(pm_vt_switch_required);
|
|
|
|
/**
|
|
* pm_vt_switch_unregister - stop tracking a device's VT switching needs
|
|
* @dev: device
|
|
*
|
|
* Remove @dev from the vt switch list.
|
|
*/
|
|
void pm_vt_switch_unregister(struct device *dev)
|
|
{
|
|
struct pm_vt_switch *tmp;
|
|
|
|
mutex_lock(&vt_switch_mutex);
|
|
list_for_each_entry(tmp, &pm_vt_switch_list, head) {
|
|
if (tmp->dev == dev) {
|
|
list_del(&tmp->head);
|
|
break;
|
|
}
|
|
}
|
|
mutex_unlock(&vt_switch_mutex);
|
|
}
|
|
EXPORT_SYMBOL(pm_vt_switch_unregister);
|
|
|
|
/*
|
|
* There are three cases when a VT switch on suspend/resume are required:
|
|
* 1) no driver has indicated a requirement one way or another, so preserve
|
|
* the old behavior
|
|
* 2) console suspend is disabled, we want to see debug messages across
|
|
* suspend/resume
|
|
* 3) any registered driver indicates it needs a VT switch
|
|
*
|
|
* If none of these conditions is present, meaning we have at least one driver
|
|
* that doesn't need the switch, and none that do, we can avoid it to make
|
|
* resume look a little prettier (and suspend too, but that's usually hidden,
|
|
* e.g. when closing the lid on a laptop).
|
|
*/
|
|
static bool pm_vt_switch(void)
|
|
{
|
|
struct pm_vt_switch *entry;
|
|
bool ret = true;
|
|
|
|
mutex_lock(&vt_switch_mutex);
|
|
if (list_empty(&pm_vt_switch_list))
|
|
goto out;
|
|
|
|
if (!console_suspend_enabled)
|
|
goto out;
|
|
|
|
list_for_each_entry(entry, &pm_vt_switch_list, head) {
|
|
if (entry->required)
|
|
goto out;
|
|
}
|
|
|
|
ret = false;
|
|
out:
|
|
mutex_unlock(&vt_switch_mutex);
|
|
return ret;
|
|
}
|
|
|
|
int pm_prepare_console(void)
|
|
{
|
|
if (!pm_vt_switch())
|
|
return 0;
|
|
|
|
orig_fgconsole = vt_move_to_console(SUSPEND_CONSOLE, 1);
|
|
if (orig_fgconsole < 0)
|
|
return 1;
|
|
|
|
orig_kmsg = vt_kmsg_redirect(SUSPEND_CONSOLE);
|
|
return 0;
|
|
}
|
|
|
|
void pm_restore_console(void)
|
|
{
|
|
if (!pm_vt_switch())
|
|
return;
|
|
|
|
if (orig_fgconsole >= 0) {
|
|
vt_move_to_console(orig_fgconsole, 0);
|
|
vt_kmsg_redirect(orig_kmsg);
|
|
}
|
|
}
|