linux-kernel - Re: [PATCH 0/8] Suspend block api (version 6)

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: <20100511180127.GB18797@srcf.ucam.org>
Date:	Tue, 11 May 2010 19:01:27 +0100
From:	Matthew Garrett <mjg@...hat.com>
To:	Tony Lindgren <tony@...mide.com>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Kevin Hilman <khilman@...prootsystems.com>,
	Arve Hjønnevåg <arve@...roid.com>,
	linux-pm@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	Alan Stern <stern@...land.harvard.edu>,
	Tejun Heo <tj@...nel.org>, Oleg Nesterov <oleg@...hat.com>,
	Paul Walmsley <paul@...an.com>, magnus.damm@...il.com,
	mark gross <mgross@...ux.intel.com>,
	Arjan van de Ven <arjan@...radead.org>,
	Geoff Smith <geoffx.smith@...el.com>,
	Brian Swetland <swetland@...gle.com>
Subject: Re: [PATCH 0/8] Suspend block api (version 6)

On Tue, May 11, 2010 at 10:48:58AM -0700, Tony Lindgren wrote:
> * Matthew Garrett <mjg@...hat.com> [100511 10:25]:
> > On Tue, May 11, 2010 at 10:24:43AM -0700, Tony Lindgren wrote:
> > 
> > > For the failed suspend path in the kernel, currently the kernel would
> > > unwind back all the drivers because of the failed driver, but that path
> > > should be possible to optimize.
> > 
> > If you think it's possible to make this work then feel free to. But at 
> > the point where you're adding code to every driver's suspend function to 
> > determine whether or not it's got any pending events that userspace 
> > hasn't consumed yet, and adding code to every bit of userspace to allow 
> > it to indicate whether or not it's busy consuming events or just busy 
> > drawing 3D bouncing cattle, I think you've reinvented suspend blocks.
> 
> Sorry, I have a working system that idles nicely and stays up on
> batteries for a long time while running. I don't need to implement
> anything like this :)

Right, but your system will only idle nicely if all of your userspace is 
well-written. It's not reasonable to expect that all userspace will be 
well-written and thus it's necessary to implement a power management 
strategy that doesn't require that. Refusing an implementation that 
achieves that on the basis that there's hypothetically a better way of 
doing it is entirely unreasonable.

-- 
Matthew Garrett | mjg59@...f.ucam.org
--
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/