Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964918AbWEBQXU (ORCPT ); Tue, 2 May 2006 12:23:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964915AbWEBQXU (ORCPT ); Tue, 2 May 2006 12:23:20 -0400 Received: from mx1.suse.de ([195.135.220.2]:17850 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S964919AbWEBQXT (ORCPT ); Tue, 2 May 2006 12:23:19 -0400 Date: Tue, 2 May 2006 09:21:36 -0700 From: Greg KH To: Bjorn Helgaas Cc: linux-pci@atrey.karlin.mff.cuni.cz, Dave Airlie , Arjan van de Ven , Andrew Morton , linux-kernel@vger.kernel.org, pjones@redhat.com Subject: Re: Add a "enable" sysfs attribute to the pci devices to allow userspace (Xorg) to enable devices without doing foul direct access Message-ID: <20060502162136.GA4668@kroah.com> References: <1146300385.3125.3.camel@laptopd505.fenrus.org> <1146301148.3125.7.camel@laptopd505.fenrus.org> <200605021014.45684.bjorn.helgaas@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200605021014.45684.bjorn.helgaas@hp.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1894 Lines: 43 On Tue, May 02, 2006 at 10:14:45AM -0600, Bjorn Helgaas wrote: > On Saturday 29 April 2006 03:04, Dave Airlie wrote: > > > > > This patch adds an "enable" sysfs attribute to each PCI device. When read it > > > shows the "enabled-ness" of the device, but you can write a "0" into it to > > > disable a device, and a "1" to enable it. > > > > > > This later is needed for X and other cases where userspace wants to enable > > > the BARs on a device (typical example: to run the video bios on a secundary > > > head). Right now X does all this "by hand" via bitbanging, that's just evil. > > > This allows X to no longer do that but to just let the kernel do this. > > > > > > Signed-off-by: Arjan van de Ven > > > CC: Peter Jones > > > CC: Dave Airlie > > > > ACK > > > > This would allow me to remove the issue in X where loading the DRM at X > > startup acts differently than loading the DRM before X runs, due to Xs PCI > > probe running in-between... with this I can just enable all VGA devices > > and no worry whether they have a DRM or not.. > > This sysfs "enable" patch seems like goodness. > > But I hope that when X uses this, it only enables & disables VGA > devices it's actually using. In the past, it seems like X has > blindly disabled *all* VGA devices in the system, even though > they might be in use by another X server. I'm sure that's all > well-understood and cleaned up now; just wanted to make sure > this nightmare didn't recur. Hopefully with the recent PCI changes to X, this will not happen. If it does, that's a big bug in X :) thanks, greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/