From: Pavel Machek <pavel@ucw.cz>
To: "Éric Piel" <eric.piel@tremplin-utc.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/4] lis3: remove automatic shutdown of the device
Date: Thu, 21 May 2009 14:08:25 +0200 [thread overview]
Message-ID: <20090521120825.GH2637@elf.ucw.cz> (raw)
In-Reply-To: <4A15411F.3050704@tremplin-utc.net>
Hi!
> >> After measurement on my laptop, it seems that turning off the device
> >> does not bring any energy saving (within 0.1W precision). So let's keep
> >> the device always on. It simplifies the code, and it avoids the problem
> >> of reading a wrong value sometimes just after turning the device on.
> >
> > Well, 0.1W is still quite much for cellphone etc... but as we do not
> > have any such small users in the tree, I guess this can go in...
> >
> Yes. BTW, what I meant is that the power consumption on my laptop can be
> read with 0.1W precision. Turning on and off the device showed 0.0W
> variations. The device should using even much less than 0.1W. According
> to the documentation, it's about 2.2mW when on and 3?W when off.
2mW would be still significant on a cellphone, draining battery in cca
20 days (which is about as bad as GSM radio), but...
If cellphone user comes, he can simply recreate powersaving code...
Feel free to add
Signed-off-by: Pavel Machek <pavel@ucw.cz>
to 2,3/4. ... And btw 4/4 probably could be pushed to 2.6.30. It is
trivial enough... and "new hw" support is okay even late in cycle.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2009-05-21 12:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-21 9:27 [PATCH 0/4] lis3: clean up and updates Éric Piel
2009-05-21 9:29 ` [PATCH 1/4] lis3: fix misc device unregistering and printk Éric Piel
2009-05-21 10:48 ` Pavel Machek
2009-05-21 9:30 ` [PATCH 2/4] lis3: remove automatic shutdown of the device Éric Piel
2009-05-21 11:36 ` Pavel Machek
2009-05-21 11:55 ` Éric Piel
2009-05-21 12:08 ` Pavel Machek [this message]
2009-05-21 9:31 ` [PATCH 3/4] lis3: use input_polled_device Éric Piel
2009-05-21 9:33 ` [PATCH 4/4] lis3: Add three new laptop models Éric Piel
2009-05-21 10:49 ` Pavel Machek
2009-05-21 11:07 ` Éric Piel
2009-05-21 11:36 ` Isaac702
[not found] ` <36a8c4f10905210424i65f5efadjdd6f13dea77cb2e6@mail.gmail.com>
2009-05-21 11:38 ` Éric Piel
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