From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3F5EECDFB8 for ; Wed, 18 Jul 2018 10:06:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 57DFD20852 for ; Wed, 18 Jul 2018 10:06:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=dtbo.net header.i=@dtbo.net header.b="Lkt8oHRQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 57DFD20852 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=dtbo.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727109AbeGRKnM (ORCPT ); Wed, 18 Jul 2018 06:43:12 -0400 Received: from mic92-4-82-224-21-170.fbx.proxad.net ([82.224.21.170]:56344 "EHLO dtbo.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726264AbeGRKnM (ORCPT ); Wed, 18 Jul 2018 06:43:12 -0400 Received: by dtbo.net (Postfix, from userid 1000) id 43DE322A0DB; Wed, 18 Jul 2018 12:06:01 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dtbo.net; s=dtbo; t=1531908361; bh=4O/mXeyWX2GFHqhUFAxCIDP7YxJAzXMJnC5gAopHu7k=; h=Date:From:To:Cc:Subject; b=Lkt8oHRQ+n+VBvLvxlb085WkHcK8rUA0KOMkU3erepNwJn03PyQrtYfbBlDvlrzxS 3u0Y6vg4PddrH7iIxldEGIsGr1OrBew0jX3rSdhFA/iYZVbK5pdcJLvTLCeLByDnn6 xXNuzy90I+qB+fvsnLcfGYTzcRn12S78IOqQQDes= Date: Wed, 18 Jul 2018 12:06:01 +0200 From: Damien =?iso-8859-1?Q?Th=E9bault?= To: Darren Hart Cc: Matthew Garrett , Pali =?iso-8859-1?Q?Roh=E1r?= , Andy Shevchenko , Mario Limonciello , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [FIXED][PATCH] dell-laptop: Fix backlight detection Message-ID: <20180718100601.GA30600@han> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fix return code check for "max brightness" ACPI call. The dell laptop ACPI video brightness control is not present on dell laptops anymore, but was present in older kernel versions. The code that checks the return value is incorrect since the SMM refactoring. The old code was: if (buffer->output[0] == 0) Which was changed to: ret = dell_send_request(...) if (ret) However, dell_send_request() will return 0 if buffer->output[0] == 0, so we must change the check to: if (ret == 0) This issue was found on a Dell M4800 laptop, and the fix tested on it as well. Fixes: 549b4930f057 ("dell-smbios: Introduce dispatcher for SMM calls") Signed-off-by: Damien Thébault Tested-by: Damien Thébault Reviewed-by: Pali Rohár Reviewed-by: Mario Limonciello --- drivers/platform/x86/dell-laptop.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c index f1fa8612db40..06978c14c83b 100644 --- a/drivers/platform/x86/dell-laptop.c +++ b/drivers/platform/x86/dell-laptop.c @@ -2185,7 +2185,7 @@ static int __init dell_init(void) dell_fill_request(&buffer, token->location, 0, 0, 0); ret = dell_send_request(&buffer, CLASS_TOKEN_READ, SELECT_TOKEN_AC); - if (ret) + if (ret == 0) max_intensity = buffer.output[3]; } -- 2.18.0