linux-kernel - Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8)

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

Message-ID: <Pine.LNX.4.44L0.1005261033440.1961-100000@iolanthe.rowland.org>
Date:	Wed, 26 May 2010 10:38:50 -0400 (EDT)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Florian Mickler <florian@...kler.org>
cc:	Vitaly Wool <vitalywool@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	<Paul@...p1.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>, <felipe.balbi@...ia.com>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	Linux PM <linux-pm@...ts.linux-foundation.org>
Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8)

On Wed, 26 May 2010, Florian Mickler wrote:

> I don't think that the in-kernel suspend block is a bad idea. 
> 
> You could probably use the suspend-blockers unconditionally in the
> suspend framework to indicate if a suspend is possible or not.

That's not how it works.  Drivers aren't supposed to abort
unconditional suspend -- not without a really good reason (for example,
the device received a wakeup event before it was fully suspended).  In
short, suspends should be considered to be _always_ possible.

> Regardless of opportunistic suspend or not. This way, you don't have to
> try-and-fail on a suspend request and thus making suspending
> potentially more robust or allowing for a "suspend as soon as
> possible" semantic (which is probably a good idea, if you have to grab
> your laptop in a hurry to get away).

That's different.  Suspend blockers could block (not abort!) regular 
suspends, just as they do opportunistic suspends.

But why should they?  I mean, if userspace wants to initiate a suspend
that is capable of being blocked by a kernel suspend blocker, then all
it has to do is initiate an opportunistic suspend instead of a normal
suspend.

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/