Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755527Ab3HCBGL (ORCPT ); Fri, 2 Aug 2013 21:06:11 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:52887 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753474Ab3HCBGJ (ORCPT ); Fri, 2 Aug 2013 21:06:09 -0400 From: "Rafael J. Wysocki" To: Felipe Contreras Cc: Aaron Lu , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, Len Brown , Zhang Rui Subject: Re: [PATCH] acpi: video: improve quirk check Date: Sat, 03 Aug 2013 03:16:22 +0200 Message-ID: <1689760.eY2GhS7V2b@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.10.0+; KDE/4.9.5; x86_64; ; ) In-Reply-To: References: <1375472229-1563-1-git-send-email-felipe.contreras@gmail.com> <3682340.ddGL4l7l22@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1796 Lines: 44 On Friday, August 02, 2013 08:04:52 PM Felipe Contreras wrote: > On Fri, Aug 2, 2013 at 6:47 PM, Rafael J. Wysocki wrote: > > On Friday, August 02, 2013 02:37:09 PM Felipe Contreras wrote: > >> If the _BCL package is descending, the first level (br->levels[2]) will > >> be 0, and if the number of levels matches the number of steps, we might > >> confuse a returned level to mean the index. > >> > >> For example: > >> > >> current_level = max_level = 100 > >> test_level = 0 > >> returned level = 100 > >> > >> In this case 100 means the level, not the index, and _BCM failed. But if > >> the _BCL package is descending, the index of level 0 is also 100, so we > >> assume _BQC is indexed, when it's not. > >> > >> This causes all _BQC calls to return bogus values causing weird behavior > >> from the user's perspective. For example: xbacklight -set 10; xbacklight > >> -set 20; would flash to 90% and then slowly down to the desired level > >> (20). > >> > >> The solution is simple; test anything other than the first level (e.g. > >> 1). > >> > >> Signed-off-by: Felipe Contreras > > > > Looks reasonable. > > > > Aaron, what do you think? > > Aaron has a similar patch does many more checks. I think we should add > more checks, but I think those should go into a separate patch. > > This patch alone fixes a real problem, which is rather urgent to fix, > and I did it this way so it's trivial to review and merge. And I still would like to know the Aaron's opinion, what's wrong with that? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/