Re: [PATCH 2/2] nouveau: use new vga_switcheroo power domain.

[Dave Airlie]

On 10 March 2016 at 00:40, Lukas Wunner <lukas@xxxxxxxxx> wrote:
> Hi Dave,
>
> On Wed, Mar 09, 2016 at 04:14:05PM +1000, Dave Airlie wrote:
>> From: Dave Airlie <airlied@xxxxxxxxxx>
>>
>> This fixes GPU auto powerdown on the Lenovo W541,
>> since we advertise Windows 2013 to the ACPI layer.
>>
>> Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
>> ---
>>  drivers/gpu/drm/nouveau/nouveau_vga.c | 10 +++++++---
>>  1 file changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/nouveau/nouveau_vga.c b/drivers/gpu/drm/nouveau/nouveau_vga.c
>> index af89c36..b987427f 100644
>> --- a/drivers/gpu/drm/nouveau/nouveau_vga.c
>> +++ b/drivers/gpu/drm/nouveau/nouveau_vga.c
>> @@ -101,8 +101,12 @@ nouveau_vga_init(struct nouveau_drm *drm)
>>               runtime = true;
>>       vga_switcheroo_register_client(dev->pdev, &nouveau_switcheroo_ops, runtime);
>>
>> -     if (runtime && nouveau_is_v1_dsm() && !nouveau_is_optimus())
>> -             vga_switcheroo_init_domain_pm_ops(drm->dev->dev, &drm->vga_pm_domain);
>> +     if (runtime) {
>> +             if (nouveau_is_v1_dsm() && !nouveau_is_optimus())
>
> The " && !nouveau_is_optimus()" can be dropped because a machine cannot
> have both. Note the "else" in nouveau_dsm_detect():

I'm pretty sure I've seen a machine with both in my past, back in the
Vista/Win7 crossover days.

> You're calling this unconditionally for all Optimus machines yet
> I assume pre Windows 10 machines lack the PR3 hooks.
>

Yes and I've confirmed on my older machine that nothing bad happens
doing it unconditionally,
and I couldn't find any bits in the _DSM flags to tell me if I should
do something different.

Dave.