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 <linux/module.h> 11 #include "power.h" 12 13 #if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE) 14 #define SUSPEND_CONSOLE (MAX_NR_CONSOLES-1) 15 16 static int orig_fgconsole, orig_kmsg; 17 static int disable_vt_switch; 18 19 /* 20 * Normally during a suspend, we allocate a new console and switch to it. 21 * When we resume, we switch back to the original console. This switch 22 * can be slow, so on systems where the framebuffer can handle restoration 23 * of video registers anyways, there's little point in doing the console 24 * switch. This function allows you to disable it by passing it '0'. 25 */ 26 void pm_set_vt_switch(int do_switch) 27 { 28 acquire_console_sem(); 29 disable_vt_switch = !do_switch; 30 release_console_sem(); 31 } 32 EXPORT_SYMBOL(pm_set_vt_switch); 33 34 int pm_prepare_console(void) 35 { 36 acquire_console_sem(); 37 38 if (disable_vt_switch) { 39 release_console_sem(); 40 return 0; 41 } 42 43 orig_fgconsole = fg_console; 44 45 if (vc_allocate(SUSPEND_CONSOLE)) { 46 /* we can't have a free VC for now. Too bad, 47 * we don't want to mess the screen for now. */ 48 release_console_sem(); 49 return 1; 50 } 51 52 if (set_console(SUSPEND_CONSOLE)) { 53 /* 54 * We're unable to switch to the SUSPEND_CONSOLE. 55 * Let the calling function know so it can decide 56 * what to do. 57 */ 58 release_console_sem(); 59 return 1; 60 } 61 release_console_sem(); 62 63 if (vt_waitactive(SUSPEND_CONSOLE)) { 64 pr_debug("Suspend: Can't switch VCs."); 65 return 1; 66 } 67 orig_kmsg = kmsg_redirect; 68 kmsg_redirect = SUSPEND_CONSOLE; 69 return 0; 70 } 71 72 void pm_restore_console(void) 73 { 74 acquire_console_sem(); 75 if (disable_vt_switch) { 76 release_console_sem(); 77 return; 78 } 79 set_console(orig_fgconsole); 80 release_console_sem(); 81 kmsg_redirect = orig_kmsg; 82 } 83 #endif 84