RE: [Acpi4asus-user] 1005PE's and backlight controls

["Wang, Yong Y" <yong.y.wang@intel.com>]

> -----Original Message-----
> From: platform-driver-x86-owner@vger.kernel.org
> [mailto:platform-driver-x86-owner@vger.kernel.org] On Behalf Of Chris
> Bagwell
> Sent: Wednesday, April 14, 2010 10:00 PM
> To: Corentin Chary
> Cc: acpi4asus-user@lists.sourceforge.net;
> platform-driver-x86@vger.kernel.org
> Subject: Re: [Acpi4asus-user] 1005PE's and backlight controls
> 
> On Wed, Apr 14, 2010 at 8:45 AM, Corentin Chary
> <corentin.chary@gmail.com> wrote:
> > On Wed, Apr 14, 2010 at 3:24 PM, Chris Bagwell <chris@cnpbagwell.com>
> wrote:
> >> On Wed, Apr 14, 2010 at 1:16 AM, Corentin Chary
> >> <corentin.chary@gmail.com> wrote:
> >>> On Wed, Apr 14, 2010 at 4:34 AM, Chris Bagwell <chris@cnpbagwell.com>
> wrote:
> >>>> Hi all,
> >>>>
> >>>> I've seen the following issue reported on various web pages but not sure if
> >>>> it was directly reported.  First up, you guys know about issue with
> acpi_osi
> >>>> of "Windows 2009" disables eeepc_backend and thats were eeepc_wmi
> comes in.
> >>>>
> >>>> There is a secondary bug though if you boot with acpi_osi="!Windows
> 2009"
> >>>> (or "Linux").  The ACPI driver will take control of backlight controls with
> >>>> Fn-F5/F6.  Those keys will work but has issues with Gnome and other
> user
> >>>> processes.
> >>>>
> >>>> Anything that uses any of the /sys/* interfaces to control backlight do not
> >>>> work correctly.  When software cycles threw levels, the behavior is kinda
> >>>> odd.  It will cycle each time you dim to something like
> >>>> Bright->Dim->Bight->Off->Bright->etc.  Also, Gnome will give no
> feedback
> >>>> because eeepc_laptop discards the events and it will not make it to
> >>>> /dev/input/event*.  And last, the status of current brightness is never
> >>>> updated under /sys/* correctly which confuses Gnome as well.
> >>>>
> >>>> The secondary work around is to add acpi_backlight=vendor to boot
> options.
> >>>> Then eepc_backlight takes charge and life is good.  Gnome gives visual
> >>>> feedback and dimmer works as expected.
> >>>>
> >>>> Baring a firmware fix from Asus, would it be possible to enable some sort
> of
> >>>> backlist for using ACPI backlight support and have 1005P's use
> eeepc_laptop?
> >>>>
> >>>> Chris
> >>>
> >>> Hi,
> >>> Did you try the eeepc-wmi ? It's the long term solution and it don't need
> >>> any extra kernel parameters. Yong Wang just added backlight support to it.
> >>>
> >>>
> http://git.kernel.org/?p=linux/kernel/git/mjg59/platform-drivers-x86.git;a=sho
> rtlog;h=refs/heads/for_linus
> >>>
> >>
> >> I havent't tried it yet but it looks like it has same issue that
> >> eeepc-laptop does.  If ACPI reports it handles backlight then
> >> eeepc-wmi disables controlling of backlight and I'd get buggy ACPI
> >> version.
> >>
> >> Does Yong happen to be on this email list?
> >
> > I don't think, but he reads platform-x86 which is now CCed
> >
> > Are you sure that the backlight behavior is the same with and without
> > acpi_osi=Linux ?
> >
> 
> I just retested to be sure and I think this confirms my suspicion that
> using eeepc-wmi will not work either for 1005PE's backlights.
> 

That is correct. Eeepc-wmi does not work on 1005PE at this moment. That is because
the ACPI BIOS of 1005PE has not fully implemented all the necessary WMI interfaces yet.
If you dump the 1005PE BIOS using acpidump, you will find that many control methods
end up calling a dummy method. We are following up this issue with ASUS and hopefully
they will fix it in later BIOS updates. Current eeepc-wmi driver has been tested on Eee PC
1008HA.

> I tried no acpi_osi (same as "WIndows 2009" I guess),
> acpi_osi="!Windows 2009", and acpi_osi="Linux"... all without
> specifying acpi_backlight=vendor.  They all had the same behaviour.
> The later two options allow eeepc-laptop to load and it always gives
> message about ACPI controlling backlight.
> 
> You can see bad behaviour easiest by using Gnome's Preferences->Power
> Management and controlling dimmer.  Sliding between 0% and 100% gives
> seemingly random behaviour.  Anything software based acts bad.
> 
> Since ACPI did seem to be controlling backlight when I didn't specify
> an acpi_osi, I suspect that means eeepc-wmi's logic to disable
> backlight support would be invoked for 1005PE's.
> 

Yes, eeepc-wmi will be loaded if acpi_osi is not specified. And if you don't specify
acpi_backlight=vendor, the generic ACPI video driver will control everything.

Thanks
-Yong

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