linux-kernel - Re: [RFC][PATCH] Power domains for platform bus type

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]

Message-ID: <Pine.LNX.4.44L0.1101312235190.11313-100000@netrider.rowland.org>
Date:	Mon, 31 Jan 2011 22:40:44 -0500 (EST)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Kevin Hilman <khilman@...com>
cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Grant Likely <grant.likely@...retlab.ca>,
	Linux-pm mailing list <linux-pm@...ts.linux-foundation.org>,
	Greg KH <greg@...ah.com>, LKML <linux-kernel@...r.kernel.org>,
	Magnus Damm <magnus.damm@...il.com>,
	Len Brown <lenb@...nel.org>
Subject: Re: [RFC][PATCH] Power domains for platform bus type

On Mon, 31 Jan 2011, Kevin Hilman wrote:

> For the on-chip SoC devices we're managing with OMAP, we're currently
> only using one set: post ops on [runtime_]suspend and pre ops on
> [runtime_]resume.
> 
> However, I could imagine (at least conceptually) using the pre ops on
> suspend to do some constraints checking and/or possibly some
> management/notification of dependent devices.  Another possiblity
> (although possibly racy) would be using the pre ops on suspend to
> initiate some high-latency operations.

Dependency management is very relevant here, since we're talking about
relations that explicitly aren't of the parent-child type.  If any of
the devices in question get marked for async suspend/resume, for
example, they certainly will need dependency handling.

> I guess the main problem with two sets is wasted space.  e.g, if I move
> OMAP to this (already hacking on it) there will be only 2 functions used
> in post ops: [runtime_]suspend() and 2 used in pre ops [runtime_]_resume().

The wasted space is minimal; we're only talking about one extra pm_ops
structure for each power domain.  Presumably any reasonable SoC isn't
going to have a tremendous number of separate power domains.  Or am I
wrong about this?

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/