Re: [PATCH v3] drm/i915: Add missing MacBook Pro models with dual channel LVDS

Jani Nikula
2015-05-05T11:24:09Z

On Mon, 04 May 2015, Lukas Wunner <lukas@wunner.de> wrote:
> Hi Ville,
>
>> I would suggest splitting that into a separate patch. Otherwise it's
>> going to harder to revert either change separately, should the need
>> arise. So that part is
>> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Okay, commit split in two as requested.

I'll look into them, thanks.

> Question:
>
> Daniel Vetter hardcoded the MacBookPro8,2 with commit
> 618563e3945b9d0864154bab3c607865b557cecc, noting:
> "Add a dual link lvds quirk for MacBook Pro 8,2
> When booting with EFI, Apple botched this one up."
>
> Nouveau recognizes just fine that dual channel LVDS is necessary,
> it seems to retrieve this information from VBIOS.
>
> On the other hand, when i915 initializes, it logs the following
> complaint (on a MacBookPro9,1): "[drm] failed to find VBIOS tables".
>
> Would it be possible to somehow point i915 to the correct location
> where it can find the VBIOS? Or can we somehow copy the VBIOS nouveau
> is using? I'm wondering, even if we had to hardcode memory locations
> to do that, wouldn't that make more sense rather than hardcoding the
> DMI IDs?

These are vendor specific bios tables we're talking about. We couldn't
readily use it anyway.

I don't really know, but looks like OS X gets the IGD info from
somewhere other than the usual VBT Windows and Linux use, while the
nvidia VBIOS is the same also on OS X. *shrug*

BR,
Jani.

>
> Thanks,
>
> Lukas

--
Jani Nikula, Intel Open Source Technology Center