Messages in this thread | | | From | <> | Date | Wed, 3 Nov 2010 16:00:20 +0100 | Subject | RE: sysfs and power management |
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>-----Original Message----- >From: ext Greg KH [mailto:gregkh@suse.de] >Sent: 03 November, 2010 15:09 >To: Alan Cox >Cc: Onkalo Samu.P (Nokia-MS/Tampere); ext Henrique de Moraes Holschuh; >Alan Cox; akpm@linux-foundation.org; linux-kernel@vger.kernel.org >Subject: Re: sysfs and power management > >On Wed, Nov 03, 2010 at 09:44:52AM +0000, Alan Cox wrote: >> On Mon, 1 Nov 2010 11:07:40 -0700 >> Greg KH <gregkh@suse.de> wrote: >> >> > On Mon, Nov 01, 2010 at 04:57:01PM +0000, Alan Cox wrote: >> > > > I took a look to that. It seems that iio is more or less sysfs >> > > > based. There are ring buffers and event device which are chardev >> > > > based but still the data outside ring buffer and the control is >> > > > sysfs based. >> > > >> > > IIO is sysfs dependant, heavyweight and makes no sense for some of >> > > the sysfs based drivers. IIO is also staging based and Linus >> > > already threw out the last attempt to unify these drivers sanely >> > > with an ALS layer - which was smaller, cleaner and better ! >> > >> > I think we need to revisit this issue again, before iio is merged to >> > the main kernel tree. I've been totally ignoring the iio >user/kernel >> > api at the moment, waiting for things to settle down there >> >> Actually I think there is another way to do it cleanly >> >> Keep a flag per device (or per runtime pm struct of device) >> >> And on the open/close do >> >> if (runtime_pm on device && device has SYSFS_PM set) >> pm_runtime_foo >> >> so that devices that need to be powered up to handle sysfs requests >can >> set a single flag and just work. > >That sounds like a reasonable idea. >
I'm working with the implementation which adds possibility to add per attribute open_close_notification method with minimal overhead to current system.
-Samu
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