From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Willy Tarreau <w@1wt.eu>
Subject: Re: NAK new drivers without proper power management?
Date: Sun, 11 Feb 2007 14:04:13 +0100
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Cc: Nigel Cunningham <nigel@nigel.suspend2.net>, Pavel Machek <pavel@ucw.cz>,
       Arjan van de Ven <arjan@infradead.org>,
       LKML <linux-kernel@vger.kernel.org>, tilman@imap.cc
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On Sunday, 11 February 2007 07:46, Willy Tarreau wrote:
[--snip--]

> What I really think would be a clean solution would be sort of
> a capability. Either the driver *is* suspend/resume-capable, and
> the system can be suspended. Or it is not, and the system must
> refuse to suspend. It should not be a problem to proceed like
> this because drivers which will not support suspend will mainly
> be those which will not have to. And if a user occasionnaly
> complains that one driver does not support it, at least you will
> have a good argument against its author to implement suspend.

I agree, but the suspend/resume safeness has to be somehow indicated by
the driver.  We could add a flag for that, but it would require us to modify
lots of existing drivers (unless there's something obvious I don't see).
However, the driver can effectively say "I'm not suspend/resume-safe" by
returning an error from .suspend(), in which case the system will automatically
refuse to suspend.

Greetings,
Rafael
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