linux-kernel - Re: regression since 2.6.36: backlight in sony-laptop not working

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Date:	Fri, 12 Nov 2010 15:38:39 +0800
From:	Zhang Rui <rui.zhang@...el.com>
To:	Norbert Preining <preining@...ic.at>
Cc:	Matthew Garrett <mjg59@...f.ucam.org>,
	Mattia Dongili <malattia@...ux.it>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	ACPI Devel Mailing List <linux-acpi@...r.kernel.org>
Subject: Re: regression since 2.6.36: backlight in sony-laptop not working

On Fri, 2010-11-12 at 11:50 +0800, Norbert Preining wrote:
> On Fr, 12 Nov 2010, Matthew Garrett wrote:
> > > Seems so that the sys files have changed to new locations:
> > > /sys/devices/virtual/backlight/acpi_video0/brightness
> > > 
> > > (mind the additional "virtual")
> > > as well as thermal zone etc etc.
> > > 
I think the /sys/class/thermal/ and /sys/class/backlight/acpi_video0
still exists, right?

we make ACPI video procfs I/F depend on CONFIG_ACPI_PROCFS, which is
cleared by default, in 2.6.36, and removed this I/F in 2.6.37-rc1.
perhaps the backlight control depends on the procfs I/F?

thanks,
rui

> > > Could that explain the problem?
> > 
> > Only if you have some wonderfully badly written software. What are you 
> > using to control the backlight? Also, I'd note that in this case your 
> > backlight is controlled via ACPI, not sony-laptop.
> 
> Ah right, yes, so probabyl sony-laptopt has nothing to do with it.
> 
> THen the problem is simply that the acpi events are not coming through
> when pressing the respective keys.
> 
> But *that* might be part of the sony-laptop kernel module?
> 
> Best wishes
> 
> Norbert
> ------------------------------------------------------------------------
> Norbert Preining            preining@...ist.ac.jp, logic.at, debian.org}
> JAIST, Japan                                 TeX Live & Debian Developer
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