From: René Bollford <xsecute@xxxxxxxxxxxxxx> Date: Sun, 23 Oct 2011 09:56:42 +0200 commit d4afc7754a60b885b63ef23fd194984e2d53a4e6 upstream. 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@xxxxxxxxxxxxxx> Signed-off-by: Matthew Garrett <mjg@xxxxxxxxxx> Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx> Tested-by: Artem X <artem.brz@xxxxxxxxx> --- Artem X wrote: > I've compiled vanilla 3.1.6 with that patch and turning off blacklight > was working. This fixes an oops reported by a few people in the new ideapad-laptop backlight driver. See: - http://thread.gmane.org/gmane.linux.kernel/1205259 - http://thread.gmane.org/gmane.linux.drivers.platform.x86.devel/2405 - http://bugs.debian.org/655377 Luckily the ideapad-laptop backlight driver was introduced in v3.1-rc1~14^2~29, so older kernels do not have this bug. Fix is already included in v3.2. 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 0c595410e788..0d94eec00f4d 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; -- 1.7.8.3 -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
