[PATCH] swsusp: add check for suspension of X-controlled devices

It is unsafe to suspend devices if the hardware is controlled by X.  Add an
extra check to prevent this from happening.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/base/power/suspend.c

@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/vt_kern.h>
 #include <linux/device.h>
 #include "../base.h"
 #include "power.h"
@@ -62,7 +63,6 @@ int suspend_device(struct device * dev, pm_message_t state)
 	return error;
 }
 
-
 /**
  *	device_suspend - Save state and stop all devices in system.
  *	@state:		Power state to put each device in.
@@ -82,6 +82,9 @@ int device_suspend(pm_message_t state)
 {
 	int error = 0;
 
+	if (!is_console_suspend_safe())
+		return -EINVAL;
+
 	down(&dpm_sem);
 	down(&dpm_list_sem);
 	while (!list_empty(&dpm_active) && error == 0) {

drivers/char/vt.c

@@ -3234,6 +3234,14 @@ void vcs_scr_writew(struct vc_data *vc, u16 val, u16 *org)
 	}
 }
 
+int is_console_suspend_safe(void)
+{
+	/* It is unsafe to suspend devices while X has control of the
+	 * hardware. Make sure we are running on a kernel-controlled console.
+	 */
+	return vc_cons[fg_console].d->vc_mode == KD_TEXT;
+}
+
 /*
  *	Visible symbols for modules
  */

include/linux/vt_kern.h

@@ -73,6 +73,11 @@ int con_copy_unimap(struct vc_data *dst_vc, struct vc_data *src_vc);
 int vt_waitactive(int vt);
 void change_console(struct vc_data *new_vc);
 void reset_vc(struct vc_data *vc);
+#ifdef CONFIG_VT
+int is_console_suspend_safe(void);
+#else
+static inline int is_console_suspend_safe(void) { return 1; }
+#endif
 
 /*
  * vc_screen.c shares this temporary buffer with the console write code so that