Re: Check for ACPI backlight support otherwise use vendor ACPIdrivers - version 4

Henrique de Moraes Holschuh
2008-08-05T13:37:53Z

On Tue, 05 Aug 2008, Yves-Alexis Perez wrote:
> On lun, 2008-08-04 at 21:01 -0300, Henrique de Moraes Holschuh wrote:
> > On Mon, 04 Aug 2008, Thomas Renninger wrote:
> > > On Monday 04 August 2008 08:09:52 Yves-Alexis Perez wrote:
> > > > When booting to single user with acpi_backlight=vendor, thinkpad-acpi
> > > > takes over backlight:
> > > >
> > > > Aug 4 07:54:38 hidalgo kernel:
> > > > thinkpad_acpi: Disabling thinkpad-acpi brightness events by default...
> >
> > See that one?
>
> Hmhm yeah but then I have:
> Aug 4 07:54:38 hidalgo kernel: thinkpad_acpi: Standard ACPI backlight interface not available, thinkpad_acpi driver will take over control

Two different subdrivers. It would be better if I added subdriver
identification to all messages, I think. hotkey is telling you it is not
issue brightness events. brightness is telling you it is going to take over
control of brightness.

> > > > But when in user mode, brightness keys doesn't do anything either.
> > > > Echo'ing to /proc/acpi/ibm/brightness doesn't work, but echoing
> > > > to /sys/class/backlight/thinkpad_screen/brightness works.
> > > That /proc/acpi/ibm/brightness does not and
> > > /sys/class/backlight/thinkpad_screen/brightness
> > > works is strange, this should be a bug?
> >
> > No. It is just that the driver expects ACPI video to be sending the events,
> > and it isn't, so you need to change some code in hotkey_init to stop
> > disabling brightness events in the (ACPI video support in DSDT, ACPI video
> > disabled and thinkpad-acpi is to handle the backlight) case.
>
> Hmhm ok, so the thinkpad-acpi related patch miss some case handling
> anyway?

Yes.

> > Please check if updating hotkey_init doesn't solve the issue. I am sorry I
> > didn't recall that detail to remind you about it when I looked your patches
> > over.
>
> How should I update hotkey_init? Check for acpi_backlight=vendor and not
> disable brightness event?

Yes. But Thomas will need to update his patch to do this, I think. Unless
ACPI video is left active enough to pass on the ACPI video change events
(but I have no idea if the DSDT will still issue those events, etc).

Thomas?

> > > > Cat'ing /proc/acpi/events still gives:
> > > > video LCD0 00000086 00000000
> > > > video LCD0 00000087 00000000
> > > >
> > > > At one time I get the 750ms delay, but I don't have the
> > > > ibm/hotkey HKEY 00000080 00005010 at all.
> >
> > This is caused by EC+ACPI DSDT access. Switch thinkpad-acpi brightness_mode
> > to use only ACPI DSDT ("CMOS" mode), and it should go away. This should be
> > the default on all Lenovo, though.
>
> Hmmh, that's weird because I don't think I'm messing with the
> brightness_mode options. But I can force it to use only CMOS mode and
> test.

Well, please check it anyway. I doubt it is that, but it can't hurt to
force brightness_mode to CMOS only.

--
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them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh