From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760622Ab2CMXOs (ORCPT ); Tue, 13 Mar 2012 19:14:48 -0400 Received: from nat.nue.novell.com ([195.135.221.2]:30310 "EHLO nat.nue.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760410Ab2CMXOq (ORCPT ); Tue, 13 Mar 2012 19:14:46 -0400 Subject: Re: [PATCH] Added backlight driver for Acer Aspire 4736 From: joeyli To: Pradeep Subrahmanion Cc: Matthew Garrett , rpurdie@rpsys.net, FlorianSchandinat@gmx.de, akpm@linux-foundation.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <1331688294.2577.19.camel@debian.Gayathri> References: <1331608337.2267.67.camel@debian.Gayathri> <20120312175130.GA18002@srcf.ucam.org> <1331640592.3485.50.camel@debian.Gayathri> <20120313124738.GB10822@srcf.ucam.org> <20120313133458.GA11574@srcf.ucam.org> <1331688294.2577.19.camel@debian.Gayathri> Content-Type: text/plain; charset="UTF-8" Date: Wed, 14 Mar 2012 07:12:53 +0800 Message-ID: <1331680373.10557.169.camel@linux-s257.site> Mime-Version: 1.0 X-Mailer: Evolution 2.28.2 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Pradeep, 於 二，2012-03-13 於 21:24 -0400，Pradeep Subrahmanion 提到： > On Tue, 2012-03-13 at 13:34 +0000, Matthew Garrett wrote: > > On Tue, Mar 13, 2012 at 06:56:16PM +0530, Pradeep Subrahmanion wrote: > > > I tried giving acpi_backlight = vendor . In that case hot key for > > > brightness control is working. But i think , it is not calculating the > > > correct value for brightness because increasing brightness after maximum > > > level gives blank screen . > > > > Which backlight device appears then? > > > > 'intel_backlight' appears when i gave option acpi_backlight = vendor. Writing to /sys/class/backlight/intel_backlight/brightness > > does not cause any change in brightness. > The above command not work, that means EC didn't change backlight value: Method (_BCM, 1, NotSerialized) { Divide (Arg0, 0x0A, Local0, Local1) Decrement (Local1) Store (Local1, ^^^^LPC.EC0.BRTS) <=== write backlight value to EC register } Per my understood, EC firmware should change brightness but didn't do that, another way is touch i915 register in _BCM. Acer machine provide a broken _BCM implementation and they didn't test it. > > > By ' ACPI interface' , I mean 'acpi_video0' inside the > > > /sys/class/backlight. I havn't tried the /sys/class/backlight interface > > > directly . I will try that also. > > > > So writing values into /sys/class/backlight/acpi_video0/brightness does > > nothing? > > > No change in value when writing > to /sys/class/backlight/acpi_video0/brightness. > > Another thing is that when i did boot with acpi_backlight = 'acer_wmi' , > in new kernel (3.3.0-rc7) , it shows following messages , > > [ 8.350825] wmi: Mapper loaded > [ 10.363975] acer_wmi: Acer Laptop ACPI-WMI Extras > [ 10.396186] acer_wmi: Function bitmap for Communication Device: 0x91 > [ 10.396385] acer_wmi: Brightness must be controlled by generic video > driver > > Also there was no interface inside /sys/class/backlight for acer_wmi. > Yes, acer_wmi support backlight control with AMW0 interface, your machine didn't have AMW0 interface. Normally, backlight should control by standard acpi interface. > I also tried writing directly to Embedded controller register .But no > change. The machine has broken _BCM method, because EC should do something after _BCM changed EC register. > ---- > > Thanks , > > Pradeep Subrahmanion > Thanks a lot! Joey Lee From mboxrd@z Thu Jan 1 00:00:00 1970 From: joeyli Date: Tue, 13 Mar 2012 23:12:53 +0000 Subject: Re: [PATCH] Added backlight driver for Acer Aspire 4736 Message-Id: <1331680373.10557.169.camel@linux-s257.site> List-Id: References: <1331608337.2267.67.camel@debian.Gayathri> <20120312175130.GA18002@srcf.ucam.org> <1331640592.3485.50.camel@debian.Gayathri> <20120313124738.GB10822@srcf.ucam.org> <20120313133458.GA11574@srcf.ucam.org> <1331688294.2577.19.camel@debian.Gayathri> In-Reply-To: <1331688294.2577.19.camel@debian.Gayathri> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Pradeep Subrahmanion Cc: Matthew Garrett , rpurdie@rpsys.net, FlorianSchandinat@gmx.de, akpm@linux-foundation.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Hi Pradeep, 於 二，2012-03-13 於 21:24 -0400，Pradeep Subrahmanion 提到： > On Tue, 2012-03-13 at 13:34 +0000, Matthew Garrett wrote: > > On Tue, Mar 13, 2012 at 06:56:16PM +0530, Pradeep Subrahmanion wrote: > > > I tried giving acpi_backlight = vendor . In that case hot key for > > > brightness control is working. But i think , it is not calculating the > > > correct value for brightness because increasing brightness after maximum > > > level gives blank screen . > > > > Which backlight device appears then? > > > > 'intel_backlight' appears when i gave option acpi_backlight = vendor. Writing to /sys/class/backlight/intel_backlight/brightness > > does not cause any change in brightness. > The above command not work, that means EC didn't change backlight value: Method (_BCM, 1, NotSerialized) { Divide (Arg0, 0x0A, Local0, Local1) Decrement (Local1) Store (Local1, ^^^^LPC.EC0.BRTS) <== write backlight value to EC register } Per my understood, EC firmware should change brightness but didn't do that, another way is touch i915 register in _BCM. Acer machine provide a broken _BCM implementation and they didn't test it. > > > By ' ACPI interface' , I mean 'acpi_video0' inside the > > > /sys/class/backlight. I havn't tried the /sys/class/backlight interface > > > directly . I will try that also. > > > > So writing values into /sys/class/backlight/acpi_video0/brightness does > > nothing? > > > No change in value when writing > to /sys/class/backlight/acpi_video0/brightness. > > Another thing is that when i did boot with acpi_backlight = 'acer_wmi' , > in new kernel (3.3.0-rc7) , it shows following messages , > > [ 8.350825] wmi: Mapper loaded > [ 10.363975] acer_wmi: Acer Laptop ACPI-WMI Extras > [ 10.396186] acer_wmi: Function bitmap for Communication Device: 0x91 > [ 10.396385] acer_wmi: Brightness must be controlled by generic video > driver > > Also there was no interface inside /sys/class/backlight for acer_wmi. > Yes, acer_wmi support backlight control with AMW0 interface, your machine didn't have AMW0 interface. Normally, backlight should control by standard acpi interface. > I also tried writing directly to Embedded controller register .But no > change. The machine has broken _BCM method, because EC should do something after _BCM changed EC register. > ---- > > Thanks , > > Pradeep Subrahmanion > Thanks a lot! Joey Lee