linux-kernel - RE: sysfs and power management

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Wed, 3 Nov 2010 16:00:20 +0100
From:	<samu.p.onkalo@...ia.com>
To:	<gregkh@...e.de>, <alan@...ux.intel.com>
CC:	<hmh@....eng.br>, <alan@...rguk.ukuu.org.uk>,
	<akpm@...ux-foundation.org>, <linux-kernel@...r.kernel.org>
Subject: RE: sysfs and power management



>-----Original Message-----
>From: ext Greg KH [mailto:gregkh@...e.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@...ux-foundation.org; linux-kernel@...r.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@...e.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




--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/