From: Greg KH <gregkh@suse.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: samu.p.onkalo@nokia.com, alan@linux.intel.com,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: sysfs and power management
Date: Fri, 29 Oct 2010 12:50:39 -0700 [thread overview]
Message-ID: <20101029195039.GA26401@suse.de> (raw)
In-Reply-To: <20101027152809.39701917@lxorguk.ukuu.org.uk>
On Wed, Oct 27, 2010 at 03:28:09PM +0100, Alan Cox wrote:
> > Do you mean per device hook and each sysfs open / close uses
> > per device ref-counting.
>
> Or you can do it by having an optional per device hook which is passed
> the sysfs node for each open/close and leave the rest up to the driver.
> If it needs to do clever stuff it can.
I really don't want to add open/close to the sysfs file model for the
driver core.
What is the specific problem with not doing any sensor work until
userspace asks for the data? Then do the read from the hardware and go
back to sleep. That's probably the best way to do this, as userspace
isn't going to open the sysfs file and not close it instantly anyway
after it has read the data (seeking on a sysfs file isn't really
recommended, even if it sometimes seems to work.)
thanks,
greg k-h
next prev parent reply other threads:[~2010-10-29 19:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-27 10:59 sysfs and power management Onkalo Samu
2010-10-27 11:48 ` Alan Cox
2010-10-27 13:43 ` samu.p.onkalo
2010-10-27 14:28 ` Alan Cox
2010-10-29 19:50 ` Greg KH [this message]
2010-10-30 14:00 ` Henrique de Moraes Holschuh
2010-10-31 11:57 ` Onkalo Samu
2010-10-31 14:25 ` Greg KH
2010-11-01 10:41 ` Onkalo Samu
2010-11-01 16:57 ` Alan Cox
2010-11-01 18:07 ` Greg KH
2010-11-03 9:44 ` Alan Cox
2010-11-03 10:48 ` samu.p.onkalo
2010-11-03 13:09 ` Greg KH
2010-11-03 15:00 ` samu.p.onkalo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20101029195039.GA26401@suse.de \
--to=gregkh@suse.de \
--cc=akpm@linux-foundation.org \
--cc=alan@linux.intel.com \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=linux-kernel@vger.kernel.org \
--cc=samu.p.onkalo@nokia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox