From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH 5/5] ACPI: Tie ACPI backlight devices to PCI devices if possible Date: Mon, 7 Feb 2011 21:34:26 +0000 Message-ID: <20110207213426.GA23843@srcf.ucam.org> References: <1295033065-13450-1-git-send-email-mjg@redhat.com> <20110206230558.GA23889@srcf.ucam.org> <201102070034.43691.rjw@sisk.pl> <201102071432.35656.bjorn.helgaas@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <201102071432.35656.bjorn.helgaas@hp.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Bjorn Helgaas Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, "Rafael J. Wysocki" , linux-acpi@vger.kernel.org, rpurdie@rpsys.net, akpm@linux-foundation.org, Len Brown List-Id: linux-acpi@vger.kernel.org On Mon, Feb 07, 2011 at 02:32:35PM -0700, Bjorn Helgaas wrote: > I'm not familiar with video devices, but I agree, this situation does > feel broken. Is it the case that there's a PCI device as well as an > ACPI namespace Device for the same piece of hardware? If so, I assume > the reason for the ACPI Device is to have a "standard" interface to > a platform knob like backlight control. > > In that case, it seems like we should rely on PCI for enumeration and > driver binding, have some sort of hook the PCI driver could use to > twiddle that knob (using the ACPI methods), and make the ACPI Device > ineligible for driver binding. In other words, it sounds like part > of the problem is that we have two drivers binding to what's really > a single piece of hardware. Part of the problem is that ACPI video devices aren't inherently PCI devices. -- Matthew Garrett | mjg59@srcf.ucam.org