[Nouveau] [PATCH v3 0/4] nouveau RPM fixes for Optimus (final)

[Alex Deucher]

On Fri, Jul 15, 2016 at 12:10 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Fri, Jul 15, 2016 at 9:12 AM, Peter Wu <peter at lekensteyn.nl> wrote:
>> Hi,
>>
>> Here are two patches to fix an issue reported on kernel bugzilla (infinite loop
>> due to unchecked function) and a more important fix to fix hanging Optimus
>> machines when runtime PM is enabled (with pm/pci patches).
>>
>> These are the final patches targeting v4.8. Changes compared to v2[1]:
>> collected R-b from Hans and Mika and fixed a minor comment style issue.
>>
>> I recommend it to be merged before the pci/pm patches[2], otherwise there is a
>> window where newer Nvidia Optimus laptops might fail to runtime resume and/or
>> lock up.  Once the pci/pm branch is merged I will propose another patch to
>> improve reliability[3].
>>
>> Known issue with patch 4: when a Nvidia HDMI audio function is present, the
>> bridge will not suspend and hence the Nvidia card will still be powered. Fixing
>
> That's basically all optimus gpu's, right? Anything GT21x+ has a HDMI
> audio subfunction, and prior to that, the nvidia gpu tended to be the
> only gpu, or hard-muxed.

I'd imagine there is a strap on the asic so the audio function is only
enabled if there is a connector actually wired to the dGPU.  It
doesn't make much sense to expose audio if there is no way to use it.

Alex