[PATCH -mm 2/3] pm: check console before suspending devices

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rjw@xxxxxxx>

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@xxxxxxx>
---
 drivers/base/power/suspend.c |    5 ++++-
 drivers/char/vt.c            |    8 ++++++++
 include/linux/vt_kern.h      |    5 +++++
 3 files changed, 17 insertions(+), 1 deletion(-)

Index: linux-2.6.16-rc6-mm2/drivers/base/power/suspend.c
===================================================================
--- linux-2.6.16-rc6-mm2.orig/drivers/base/power/suspend.c
+++ linux-2.6.16-rc6-mm2/drivers/base/power/suspend.c
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/vt_kern.h>
 #include <linux/device.h>
 #include <linux/kallsyms.h>
 #include <linux/pm.h>
@@ -65,7 +66,6 @@ int suspend_device(struct device * dev, 
 	return error;
 }
 
-
 /**
  *	device_suspend - Save state and stop all devices in system.
  *	@state:		Power state to put each device in.
@@ -85,6 +85,9 @@ 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) {
Index: linux-2.6.16-rc6-mm2/drivers/char/vt.c
===================================================================
--- linux-2.6.16-rc6-mm2.orig/drivers/char/vt.c
+++ linux-2.6.16-rc6-mm2/drivers/char/vt.c
@@ -3234,6 +3234,14 @@ void vcs_scr_writew(struct vc_data *vc, 
 	}
 }
 
+/* It is unsafe to suspend devices while X has control of the
+ * hardware. Check if we are running on a kernel-controlled console.
+ */
+int is_console_suspend_safe(void)
+{
+	return vc_cons[fg_console].d->vc_mode == KD_TEXT;
+}
+
 /*
  *	Visible symbols for modules
  */
Index: linux-2.6.16-rc6-mm2/include/linux/vt_kern.h
===================================================================
--- linux-2.6.16-rc6-mm2.orig/include/linux/vt_kern.h
+++ linux-2.6.16-rc6-mm2/include/linux/vt_kern.h
@@ -73,6 +73,11 @@ int con_copy_unimap(struct vc_data *dst_
 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

-
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