From: Ben Dooks Date: Wed, 19 Nov 2008 23:36:25 +0000 (-0800) Subject: lcd: fix oops if driver only interested in .set_power X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b3b4dc8840a8fdbe495723d35cd976d781fd42fa;p=linux-beck.git lcd: fix oops if driver only interested in .set_power 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c index 8e1731d3b228..680e57b616cd 100644 --- a/drivers/video/backlight/lcd.c +++ b/drivers/video/backlight/lcd.c @@ -42,10 +42,13 @@ static int fb_notifier_callback(struct notifier_block *self, 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;