highres: improve debug output

Add some more debug information to the hrtimer and clock events code.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index f6997ab..0258d31 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -73,8 +73,21 @@
 	struct clock_event_device *dev = td->evtdev;
 
 	if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
-	    !tick_device_is_functional(dev))
+		    !tick_device_is_functional(dev)) {
+
+		printk(KERN_INFO "Clockevents: "
+		       "could not switch to one-shot mode:");
+		if (!dev) {
+			printk(" no tick device\n");
+		} else {
+			if (!tick_device_is_functional(dev))
+				printk(" %s is not functional.\n", dev->name);
+			else
+				printk(" %s does not support one-shot mode.\n",
+				       dev->name);
+		}
 		return -EINVAL;
+	}
 
 	td->mode = TICKDEV_MODE_ONESHOT;
 	dev->event_handler = handler;