linux-kernel - Re: [PATCH 5/5] ACPI: Tie ACPI backlight devices to PCI devices if possible

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 7 Feb 2011 21:34:26 +0000
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	Bjorn Helgaas <bjorn.helgaas@...com>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>, dri-devel@...ts.freedesktop.org,
	akpm@...ux-foundation.org, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, rpurdie@...ys.net,
	Len Brown <lenb@...nel.org>
Subject: Re: [PATCH 5/5] ACPI: Tie ACPI backlight devices to PCI devices if
	possible

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@...f.ucam.org
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/