linux-kernel - Re: [RFC PATCH 7/7] drm/pci: Defer initialization of secondary graphics devices until switcheroo is ready

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Mon, 20 Aug 2012 10:56:33 -0500
From:	Seth Forshee <seth.forshee@...onical.com>
To:	Matthew Garrett <mjg59@...f.ucam.org>
Cc:	Dave Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
	David Airlie <airlied@...ux.ie>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	Andreas Heider <andreas@...tr.de>
Subject: Re: [RFC PATCH 7/7] drm/pci: Defer initialization of secondary
 graphics devices until switcheroo is ready

On Mon, Aug 20, 2012 at 04:36:40PM +0100, Matthew Garrett wrote:
> On Mon, Aug 20, 2012 at 10:31:04AM -0500, Seth Forshee wrote:
> > +	/*
> > +	 * For secondary graphics devices shouldn't be initialized
> > +	 * until the handler and primary graphics device have been
> > +	 * registered with vga_switcheroo.
> > +	 *
> > +	 * FIXME: Is vga_default_device() reliable enough for this
> > +	 * purpose?
> > +	 *
> > +	 * FIXME: If vga_switcheroo is disabled secondary devices
> > +	 * never gets initialized. Is this okay? Maybe it is, since
> > +	 * we can't switch to the secondary GPU anyway.
> > +	 */
> 
> Won't this break the multiple cards with independent outputs case?

Yes, if they don't have a switcheroo handler. I only have experience
with one such machine, which had optimus graphics. My recollection is
that it did have a switcheroo handler, which was only capable of
controlling power to the discrete card.

--
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/