From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: [PATCH 5/5] ACPI: Tie ACPI backlight devices to PCI devices if possible
Date: Sun, 6 Feb 2011 23:41:19 +0100
Message-ID: <201102062341.19631.rjw@sisk.pl>
References: <1295033065-13450-1-git-send-email-mjg@redhat.com> <201102062135.08171.rjw@sisk.pl> <20110206205619.GA21472@srcf.ucam.org>
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To: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: akpm@linux-foundation.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, rpurdie@rpsys.net
List-Id: dri-devel@lists.freedesktop.org

On Sunday, February 06, 2011, Matthew Garrett wrote:
> On Sun, Feb 06, 2011 at 09:35:07PM +0100, Rafael J. Wysocki wrote:
> > > +		acpi_get_parent(device->dev->handle, &acpi_parent);
> > > +
> > > +		pdev = acpi_get_pci_dev(acpi_parent);
> > > +		if (pdev) {
> > > +			parent = &pdev->dev;
> > > +			pci_dev_put(pdev);
> > > +		}
> > 
> > I'm afraid you can't do that or suspend problems will happen.
> 
> Ugh. Ok, how can we fix this?

Not nicely, I'm afraid.

One possible way is to use device_pm_move_after() to rearrange the devices in
the PM core's suspend list, but that will happen in the video device being
suspended before the new parent (and resumed after it) -- of course, the only
option is to move the ACPI video device after the new parent.

Thanks,
Rafael