From b3b4dc8840a8fdbe495723d35cd976d781fd42fa Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Wed, 19 Nov 2008 15:36:25 -0800 Subject: [PATCH] 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 --- drivers/video/backlight/lcd.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c index 8e1731d3b22..680e57b616c 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; -- 2.41.0