From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH] Re: NAK new drivers without proper power management? Date: Sun, 11 Feb 2007 12:13:40 +0000 Message-ID: <20070211121339.GB4204@srcf.ucam.org> References: <200702101130.44471.rjw@sisk.pl> <200702102050.28218.rjw@sisk.pl> <20070211065404.GA943@1wt.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20070211065404.GA943@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org To: Willy Tarreau Cc: "Rafael J. Wysocki" , Daniel Barkalow , nigel@nigel.suspend2.net, Robert Hancock , linux-kernel , Jeff Garzik , Pavel Machek , pm list List-Id: linux-pm@vger.kernel.org On Sun, Feb 11, 2007 at 07:54:04AM +0100, Willy Tarreau wrote: > instead of modifying all drivers to explicitly state that they don't support > it, we should start with a test of the NULL pointer for .suspend which should > mean exactly the same without modifying the drivers. I find it obvious that > a driver which does provide a suspend function will not support it. And if > some drivers (eg /dev/null) can support it anyway, it's better to change > *those* drivers to explicitly mark them as compatible. No, that doesn't work. In the absence of suspend/resume methods, the PCI layer will implement basic PM itself. In some cases, this works. In others, it doesn't. There's no way to automatically determine which is which without modifying the drivers. -- Matthew Garrett | mjg59@srcf.ucam.org