+ lcd-fix-oops-if-driver-only-interested-in-set_power.patch added to -mm tree

+ lcd-fix-oops-if-driver-only-interested-in-set_power.patch added to -mm tree

[akpm]

The patch titled
     lcd: fix oops if driver only interested in .set_power
has been added to the -mm tree.  Its filename is
     lcd-fix-oops-if-driver-only-interested-in-set_power.patch

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------------------------------------------------------
Subject: lcd: fix oops if driver only interested in .set_power
From: Ben Dooks <ben-linux@fluff.org>

The LCD driver core calls LCD drivers when either the blanking state or
the display mode has changed, but does not make any check to see if the
called driver has a .set_mode method.

This means if a driver only has a .set_power method then the system will
OOPS on changing mode (and with the console semaphore held so you cannot
easily see the problem).

Fix the problem by ensuring that either callback is valid before use.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/video/backlight/lcd.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff -puN drivers/video/backlight/lcd.c~lcd-fix-oops-if-driver-only-interested-in-set_power drivers/video/backlight/lcd.c
--- a/drivers/video/backlight/lcd.c~lcd-fix-oops-if-driver-only-interested-in-set_power
+++ a/drivers/video/backlight/lcd.c
@@ -42,10 +42,13 @@ static int fb_notifier_callback(struct n
 
 	mutex_lock(&ld->ops_lock);
 	if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) {
-		if (event == FB_EVENT_BLANK)
-			ld->ops->set_power(ld, *(int *)evdata->data);
-		else
-			ld->ops->set_mode(ld, evdata->data);
+		if (event == FB_EVENT_BLANK) {
+			if (ld->ops->set_power)
+				ld->ops->set_power(ld, *(int *)evdata->data);
+		} else {
+			if (ld->ops->set_mode)
+				ld->ops->set_mode(ld, evdata->data);
+		}
 	}
 	mutex_unlock(&ld->ops_lock);
 	return 0;
_

Patches currently in -mm which might be from ben-linux@fluff.org are

lcd-fix-oops-if-driver-only-interested-in-set_power.patch