linux-kernel - Re: 3.14-rc: /proc/acpi/battery gone?

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Date:	Sun, 20 Apr 2014 15:09:30 +0200
From:	Pavel Machek <pavel@....cz>
To:	Ilia Mirkin <imirkin@...m.mit.edu>
Cc:	Stefan Lippers-Hollmann <s.L-H@....de>,
	Lan Tianyu <tianyu.lan@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	kernel list <linux-kernel@...r.kernel.org>
Subject: Re: 3.14-rc: /proc/acpi/battery gone?

Hi!

> >>       I just glance wmbattery code. I find the code in the acpi.c is already
> >> using the new sysfs battery interfaces, right?
> >
> > By default, wmbattery appears to default to using upower as abstraction
> > level, instead of querying sysfs itself directly.
> >
> > http://git.kitenet.net/?p=wmbattery.git;a=blob;f=autoconf/makeinfo.in;hb=HEAD
> >
> > which sets USE_UPOWER=1 by default.
> >
> > If USE_UPOWER=0 is set explicitly for the build, it reverts back to
> > direct sysfs parsing - and yes, it does appear to adhere to the current
> > sysfs API properly.
> >
> > The last remains, and the ability to parse procfs (which hasn't been
> > default for quite some time already, in favour of using hal as
> > abstraction layer) has finally been removed in
> >
> > http://git.kitenet.net/?p=wmbattery.git;a=commitdiff;h=833eb63a5ce4f2fb712a201b1db4f2db1700fddb
> >
> > The switch from procfs parsing to hal (by default at least) in turn
> > happened with
> >
> > http://git.kitenet.net/?p=wmbattery.git;a=commitdiff;h=63c3d1a0b11e8ade1a5612bb5baa3d92e153bbbe
> >
> > in 2008 (before Debian squeeze/ oldstable). I have not investigated if
> > hal then read from procfs or sysfs, but wmbattery at least didn't read
> > from procfs itself, unless explicitly told to do so (USE_HAL=0) during
> > the build since mid 2008.
> >
> > The current version of wmbattery however will never try to access
> > /proc/acpi, the current version no longer knows of its existence.
> >
> > [Again, I'm not familiar with wmbattery myself and have never run it]
> 
> Stefan,
> 
> Thanks for looking into this. The newest wmbattery version indeed
> supports upower. However, I haven't figured out how to get it to work.
> That's obviously not the kernel's fault, but an unfortunate reality.
> It seems to really want dbus to be running, but when I start dbus
> (which nothing else on my system needs, apparently), it just hangs. My
> knowledge of these things is, (un)fortunately non-existent, so I just
> gave up on the upower approach. Running something as heavy as dbus
> just for a silly dock app seems... silly as well.

Any news on this one?

It seems that delaying fsck on battery power also relies on
/proc/acpi/battery...

https://bbs.archlinux.org/viewtopic.php?id=12168

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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