[Intel-gfx] i915 module does not find 82865G if configured as secondary

Chris Wilson chris at chris-wilson.co.uk
Sun Oct 9 20:36:27 CEST 2011

On Sun, 9 Oct 2011 14:44:30 +0200, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Sun, Oct 09, 2011 at 01:07:25PM +0200, Tempura San wrote:
> > Here is the output of lspci -nn:
> > 
> > 00:00.0 Host bridge [0600]: Intel Corporation 82865G/PE/P DRAM
> > Controller/Host-Hub Interface [8086:2570] (rev 02)
> > 00:02.0 Display controller [0380]: Intel Corporation 82865G Integrated
> > Graphics Controller [8086:2572] (rev 02)
> The issue seems to be that the igd isn't a VGA pci class device anymore
> when used as secondary. The below (untested) patch should allow to still
> bind the i915 driver. Please test how far that gets us.

Note the old kernel, and probable lack of:

commit 934f992c763ae1e5eefcce8af769c16444085df7
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Thu Jan 20 13:09:12 2011 +0000

    drm/i915: Recognise non-VGA display devices
    Starting with SandyBridge (though possible with earlier hacked BIOSes),
    the BIOS may initialise the IGFX as secondary to a discrete GPU. Prior,
    it would simply disable the integrated GPU. So we adjust our PCI class
    mask to match any DISPLAY_CLASS device.
    In such a configuration, the IGFX is not a primary VGA controller and
    so should not take part in VGA arbitration, and the error return from
    vga_client_register() is expected.
    Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
    Cc: stable at kernel.org


commit 5fe49d86f9d01044abf687a8cd21edef636d58aa
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Tue Feb 1 19:43:02 2011 +0000

    drm/i915: Only bind to function 0 of the PCI device
    Early chipsets (gen2/3) used function 1 as a placeholder for multi-head.
    We used to ignore these since they were not assigned to
    PCI_CLASS_DISPLAY_VGA. However with 934f992c7 we attempt to bind to all
    Intel PCI_CLASS_DISPLAY devices (and functions) to work in multi-gpu
    systems. This fails hard on gen2/3.
    Reported-by: Ferenc Wágner <wferi at niif.hu>
    Tested-by: Ferenc Wágner <wferi at niif.hu>
    Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=28012
    Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
    Cc: stable at kernel.org

Chris Wilson, Intel Open Source Technology Centre

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