From: joeyli <jlee@suse.com> To: Pradeep Subrahmanion <subrahmanion.pradeep@gmail.com> Cc: Matthew Garrett <mjg@redhat.com>, rpurdie@rpsys.net, FlorianSchandinat@gmx.de, akpm@linux-foundation.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Added backlight driver for Acer Aspire 4736 Date: Wed, 14 Mar 2012 13:51:18 +0800 [thread overview] Message-ID: <1331704278.10557.190.camel@linux-s257.site> (raw) In-Reply-To: <1331692996.3052.8.camel@debian.Gayathri> 於 三,2012-03-14 於 08:13 +0530,Pradeep Subrahmanion 提到: > Hi Joey , > > > Per my understood, EC firmware should change brightness but didn't do > > that, another > > way is touch i915 register in _BCM. > > how do we do this ? you mean change the _BCM implementation ? "BIOS guy" should do something like this: Method (AINT, 2, NotSerialized) { ... If (LEqual (Arg0, One)) { Store (Divide (Multiply (Arg1, 0xFF), 0x64, ), BCLP) Or (BCLP, 0x80000000, BCLP) <=== touch BCLP register Store (0x02, ASLC) } Method (_BCM, 1, NotSerialized) { If (LAnd (LGreaterEqual (Arg0, Zero), LLessEqual (Arg0, 0x64))) { AINT (One, Arg0) <=== call AINT method Store (Arg0, BRTL) } } Just for reference, they should do that when EC didn't wire to backlight. > > > > 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 Why they didn't find _BCM not work? My guess is: Because the backlight control is through WDDM driver on Windows platform but not through standard ACPI method _BCM. They only test Windows platform, so, they didn't find _BCM broken. And, they also didn't really follow Microsoft WDDM spec: http://msdn.microsoft.com/en-us/windows/hardware/gg487382.aspx Per spec, ODM should keep _BCM works fine for any other OS didn't support WDDM driver, but they didn't. At last year, I told Acer PM one time for this issue, they said will check but finally didn't response me. Thanks Joey Lee
WARNING: multiple messages have this Message-ID (diff)
From: joeyli <jlee@suse.com> To: Pradeep Subrahmanion <subrahmanion.pradeep@gmail.com> Cc: Matthew Garrett <mjg@redhat.com>, rpurdie@rpsys.net, FlorianSchandinat@gmx.de, akpm@linux-foundation.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Added backlight driver for Acer Aspire 4736 Date: Wed, 14 Mar 2012 05:51:18 +0000 [thread overview] Message-ID: <1331704278.10557.190.camel@linux-s257.site> (raw) In-Reply-To: <1331692996.3052.8.camel@debian.Gayathri> 於 三,2012-03-14 於 08:13 +0530,Pradeep Subrahmanion 提到: > Hi Joey , > > > Per my understood, EC firmware should change brightness but didn't do > > that, another > > way is touch i915 register in _BCM. > > how do we do this ? you mean change the _BCM implementation ? "BIOS guy" should do something like this: Method (AINT, 2, NotSerialized) { ... If (LEqual (Arg0, One)) { Store (Divide (Multiply (Arg1, 0xFF), 0x64, ), BCLP) Or (BCLP, 0x80000000, BCLP) <== touch BCLP register Store (0x02, ASLC) } Method (_BCM, 1, NotSerialized) { If (LAnd (LGreaterEqual (Arg0, Zero), LLessEqual (Arg0, 0x64))) { AINT (One, Arg0) <== call AINT method Store (Arg0, BRTL) } } Just for reference, they should do that when EC didn't wire to backlight. > > > > 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 Why they didn't find _BCM not work? My guess is: Because the backlight control is through WDDM driver on Windows platform but not through standard ACPI method _BCM. They only test Windows platform, so, they didn't find _BCM broken. And, they also didn't really follow Microsoft WDDM spec: http://msdn.microsoft.com/en-us/windows/hardware/gg487382.aspx Per spec, ODM should keep _BCM works fine for any other OS didn't support WDDM driver, but they didn't. At last year, I told Acer PM one time for this issue, they said will check but finally didn't response me. Thanks Joey Lee
next prev parent reply other threads:[~2012-03-14 5:53 UTC|newest] Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <CABNxG=CU+bOWUauLYfcS2vtFqKvXA-9axgokNoYz+KuU1Mzztw@mail.gmail.com> 2012-03-11 19:42 ` [PATCH] Added backlight driver for Acer Aspire 4736 Florian Tobias Schandinat 2012-03-11 19:42 ` Florian Tobias Schandinat 2012-03-12 17:36 ` Pradeep Subrahmanion 2012-03-13 3:12 ` Pradeep Subrahmanion 2012-03-12 17:51 ` Matthew Garrett 2012-03-13 12:09 ` Pradeep Subrahmanion 2012-03-13 12:47 ` Matthew Garrett 2012-03-13 13:29 ` Pradeep Subrahmanion 2012-03-13 13:41 ` Pradeep Subrahmanion [not found] ` <CABNxG=Dqg26EHmC3vibf3-SjVhby1qgQfMniQObUeh9eJ6SwEw@mail.gmail.com> 2012-03-13 13:34 ` Matthew Garrett 2012-03-13 15:49 ` Pradeep Subrahmanion 2012-03-14 1:24 ` Pradeep Subrahmanion 2012-03-13 23:12 ` joeyli 2012-03-13 23:12 ` joeyli 2012-03-14 2:43 ` Pradeep Subrahmanion 2012-03-14 2:55 ` Pradeep Subrahmanion 2012-03-14 5:51 ` joeyli [this message] 2012-03-14 5:51 ` joeyli 2012-03-14 6:17 ` Pradeep Subrahmanion 2012-03-14 6:29 ` Pradeep Subrahmanion 2012-03-15 8:05 ` joeyli 2012-03-15 8:05 ` joeyli 2012-03-18 5:10 ` Pradeep Subrahmanion 2012-03-18 5:22 ` Pradeep Subrahmanion 2012-03-19 2:01 ` joeyli 2012-03-19 2:01 ` joeyli 2012-03-19 11:33 ` Pradeep Subrahmanion 2012-03-19 11:45 ` Pradeep Subrahmanion 2012-03-20 3:55 ` joeyli 2012-03-20 3:55 ` joeyli 2012-03-20 11:09 ` joeyli 2012-03-20 11:09 ` joeyli 2012-03-20 18:55 ` Pradeep Subrahmanion 2012-03-20 18:55 ` Pradeep Subrahmanion 2012-03-21 3:00 ` joeyli 2012-03-21 3:00 ` joeyli 2012-03-21 19:09 ` Pradeep Subrahmanion 2012-03-21 19:21 ` Pradeep Subrahmanion 2012-03-22 1:33 ` joeyli 2012-03-22 1:33 ` joeyli 2012-03-22 2:33 ` Pradeep Subrahmanion 2012-03-22 2:45 ` Pradeep Subrahmanion 2012-03-22 3:25 ` joeyli 2012-03-22 3:25 ` joeyli 2012-03-22 3:32 ` Pradeep Subrahmanion 2012-03-22 3:44 ` Pradeep Subrahmanion 2012-03-22 3:54 ` joeyli 2012-03-22 3:54 ` joeyli 2012-03-22 5:56 ` Pradeep Subrahmanion 2012-03-22 5:57 ` Pradeep Subrahmanion 2012-03-22 9:34 ` joeyli 2012-03-22 9:34 ` joeyli 2012-03-22 16:17 ` Pradeep Subrahmanion 2012-03-22 16:29 ` Pradeep Subrahmanion 2012-03-23 3:36 ` Pradeep Subrahmanion 2012-03-23 3:48 ` Pradeep Subrahmanion 2012-03-23 4:25 ` joeyli 2012-03-23 4:25 ` joeyli 2012-03-18 5:12 ` Pradeep Subrahmanion 2012-03-18 5:24 ` Pradeep Subrahmanion 2012-03-12 23:07 ` Joe Perches 2012-03-12 23:07 ` Joe Perches 2012-03-12 17:40 ` Pradeep Subrahmanion 2012-03-13 3:16 ` Pradeep Subrahmanion 2012-03-13 3:10 ` joeyli 2012-03-13 3:10 ` joeyli 2012-03-13 13:12 ` Pradeep Subrahmanion 2012-03-13 4:35 ` joeyli 2012-03-13 4:35 ` joeyli
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