From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH] ACPI video: Be more liberal in validating _BQC behaviour Date: Mon, 22 Feb 2010 02:06:47 +0000 Message-ID: <20100222020647.GA30278@srcf.ucam.org> References: <1266357230-10602-1-git-send-email-mjg@redhat.com> <20100219135431.GA29434@srcf.ucam.org> <1266803479.2608.1484.camel@rzhang1-desktop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([93.93.128.6]:56776 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754119Ab0BVCG6 (ORCPT ); Sun, 21 Feb 2010 21:06:58 -0500 Content-Disposition: inline In-Reply-To: <1266803479.2608.1484.camel@rzhang1-desktop> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Zhang Rui Cc: Len Brown , "linux-acpi@vger.kernel.org" On Mon, Feb 22, 2010 at 09:51:19AM +0800, Zhang Rui wrote: > On Fri, 2010-02-19 at 21:54 +0800, Matthew Garrett wrote: > > My system statically initialises the variable containing the current > > brightness to 100, but doesn't include 100 in the list of valid > > brightnesses. > > sorry, I don't understand. > does the video driver set the backlight to 100, which is not a valid > value in the _BCL package? No, the firmware does. > > Right now this causes us to stop believing _BQC. However, > > the enxt thing we do is set the brightness to maximum anyway - at this > > point _BQC will now return a correct value. > > hmmm, could you attach the acpidump please? The relevant bits are: Name (BRIG, 0x64) Method (_BQC, 0, Serialized) { Store (BRIG, Local0) Return (Local0) } Method (_BCM, 1, Serialized) { ... Store (Arg0, BRIG) 0x64 is an invalid value as far as _BCL goes. So, _BQC will give an invalid response until we set a value - after that, it'll be correct. -- Matthew Garrett | mjg59@srcf.ucam.org