/* * 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(); kmsg_redirect = orig_kmsg; } #endif