From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756651Ab2APSuE (ORCPT ); Mon, 16 Jan 2012 13:50:04 -0500 Received: from cantor2.suse.de ([195.135.220.15]:43088 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756575Ab2APSt7 (ORCPT ); Mon, 16 Jan 2012 13:49:59 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Mon Jan 16 10:45:17 2012 Message-Id: <20120116184517.406491648@clark.kroah.org> User-Agent: quilt/0.50-25.1 Date: Mon, 16 Jan 2012 10:44:46 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Rene Bolldorf , Matthew Garrett , Jonathan Nieder Subject: [19/48] [PATCH] ideapad: Check if acpi already handle backlight power to avoid a page fault In-Reply-To: <20120116184527.GA11972@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rene Bollford 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 Signed-off-by: Matthew Garrett Signed-off-by: Jonathan Nieder Tested-by: Artem X Signed-off-by: Greg Kroah-Hartman --- drivers/platform/x86/ideapad-laptop.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/platform/x86/ideapad-laptop.c +++ b/drivers/platform/x86/ideapad-laptop.c @@ -493,6 +493,8 @@ static void ideapad_backlight_notify_pow 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;