On Fri, Sep 26, 2014 at 5:08 PM, Aaron Plattner <aplattner@xxxxxxxxxx> wrote: > On 09/23/2014 01:29 PM, Benjamin Herrenschmidt wrote: >> >> On Mon, 2014-09-22 at 13:43 -0700, Linus Torvalds wrote: >>> >>> Adding proper people and mailing lists.. >>> >>> The PCI_CLASS_DISPLAY_VGA test goes back to the very beginning by >>> BenH, and I have no idea if adding PCI_CLASS_DISPLAY_3D is >>> appropriate, but hopefully somebody does. The fact that it makes >>> things work certainly argues fairly convincingly for it, but I want >>> some backup here. >>> >>> Dave, BenH? >>> >>> Christopher(?), can you please also specify which laptop etc. And the >>> patch itself seems to have come from somebody else, unless you're >>> Lekensteyn. So we'd want to get the provenance of that too. >> >> >> Hrm, that sucks. "3D" could mean anything really, we might need an >> explicit vendor ID check as well and maybe even device ID ... > > > If my understanding is correct, the board designers explicitly mark them as > "3D controller" when they don't have any outputs connected, specifically so > the SBIOS won't choose them as the boot VGA device. Depending on the design, > some GPUs on these 3D controller boards don't have a display engine at all, > while others still have it in the silicon but leave it disabled at runtime. > In either case, VGA should not be routed to them and I don't think they > should need to participate in VGA arbitration. Without commenting on the vga aspects of this discussion (about which I know next to nothing), I'm moderately sure the nouveau team has seen optimus setups where the secondary GPU reports itself as a 3d controller, but has a working display engine, and outputs connected to it. And I believe the inverse has also happened (a device that reports itself as VGA but has no outputs advertised and a potentially-absent display engine). -ilia _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
