From d4afc7754a60b885b63ef23fd194984e2d53a4e6 Mon Sep 17 00:00:00 2001
From: Rene Bollford <xsecute@googlemail.com>
Date: Sun, 23 Oct 2011 09:56:42 +0200
Subject: [PATCH] [PATCH] ideapad: Check if acpi already handle backlight
power to avoid a page fault
This patch avoid a page fault in the ideapad-laptop extras when
turning the backlight power on or off.
Signed-off-by: Rene Bolldorf <xsecute@googlemail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
drivers/platform/x86/ideapad-laptop.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
index 0c59541..0d94eec 100644
--- a/drivers/platform/x86/ideapad-laptop.c
+++ b/drivers/platform/x86/ideapad-laptop.c
@@ -493,6 +493,8 @@ static void ideapad_backlight_notify_power(struct ideapad_private *priv)
unsigned long power;
struct backlight_device *blightdev = priv->blightdev;
+ if (!blightdev)
+ return;
if (read_ec_data(ideapad_handle, 0x18, &power))
return;
blightdev->props.power = power ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;
--
1.7.6.4