linux-kernel - Re: [RFD] Automatic suspend

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 for Android: free password hash cracker in your pocket

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

Date:	Fri, 27 Feb 2009 09:46:16 -0500 (EST)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Pavel Machek <pavel@....cz>
cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Oliver Neukum <oliver@...kum.org>,
	Arve Hj?nnev?g <arve@...roid.com>,
	"Woodruff, Richard" <r-woodruff2@...com>,
	Arjan van de Ven <arjan@...radead.org>,
	Kyle Moffett <kyle@...fetthome.net>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Nigel Cunningham <nigel@...el.suspend2.net>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	mark gross <mgross@...ux.intel.com>,
	Uli Luckas <u.luckas@...d.de>,
	Igor Stoppa <igor.stoppa@...ia.com>,
	Brian Swetland <swetland@...gle.com>,
	Len Brown <lenb@...nel.org>
Subject: Re: [RFD] Automatic suspend

On Fri, 27 Feb 2009, Pavel Machek wrote:

> 
> > To summarize, we can:
> > * Use a refcount such that automatic suspend will only be possible if it's
> >   equal to zero (but that need not be the only criterion).
> > * Use a per-device flag in dev_pm_info that will be set whenever the device
> >   driver increases the refcount and unset whenever the driver decreases the
> >   refcount.
> > * Use a per-process flag that will be set whenever the process increases the
> >   refcount and unset whenever the process decreases the refcount.
> 
> Yes, that sounds sane, and that's how reasonable wakelock
> implementation should look like.

One small point: If you add a per-device flag and a per-process flag as 
described above, then drivers and processes must not acquire nested 
references.

Obviously this is fixable, but it's worth mentioning...

Alan Stern

--
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/