[PATCH] drm/i915: refine qemu south bridge detection

[Jani Nikula]

On Mon, 25 Jan 2016, Gerd Hoffmann <kraxel at redhat.com> wrote:
> The test for the qemu q35 south bridge added by commit
> "39bfcd52 drm/i915: more virtual south bridge detection"
> also matches on real hardware.  Having the check for
> virtual systems last in the list is not enough to avoid
> that ...
>
> Refine the check by additionally verifying the pci
> subsystem id to see whenever it *really* is qemu.
>
> Reported-by: Bjørn Mork <bjorn at mork.no>
> Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>

Already sent the revert in [1], but I'm fine with this if it works for
Bjørn.

BR,
Jani.

[1] http://mid.gmane.org/1453710360-30099-1-git-send-email-jani.nikula@intel.com


> ---
>  drivers/gpu/drm/i915/i915_drv.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 3ac616d..9668162 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -501,7 +501,9 @@ void intel_detect_pch(struct drm_device *dev)
>  				WARN_ON(!IS_SKYLAKE(dev) &&
>  					!IS_KABYLAKE(dev));
>  			} else if ((id == INTEL_PCH_P2X_DEVICE_ID_TYPE) ||
> -				   (id == INTEL_PCH_QEMU_DEVICE_ID_TYPE)) {
> +				   ((id == INTEL_PCH_QEMU_DEVICE_ID_TYPE) &&
> +				    pch->subsystem_vendor == 0x1a4f &&
> +				    pch->subsystem_device == 0x1100)) {
>  				dev_priv->pch_type = intel_virt_detect_pch(dev);
>  			} else
>  				continue;

-- 
Jani Nikula, Intel Open Source Technology Center