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

Lukas Wunner
2016-03-15T20:46:24Z

Hi Dave,

On Thu, Mar 10, 2016 at 08:04:26AM +1000, Dave Airlie wrote:
> On 10 March 2016 at 00:40, Lukas Wunner <lukas@wunner.de> wrote:
> > On Wed, Mar 09, 2016 at 04:14:05PM +1000, Dave Airlie wrote:
> >> From: Dave Airlie <airlied@redhat.com>
> >>
> >> This fixes GPU auto powerdown on the Lenovo W541,
> >> since we advertise Windows 2013 to the ACPI layer.
> >>
> >> Signed-off-by: Dave Airlie <airlied@redhat.com>
> >> ---
> >> 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.

Yes, but the code in nouveau_dsm_detect() is such that you'll never have
both nouveau_is_v1_dsm() and nouveau_is_optimus() return true.

So you can drop the " && !nouveau_is_optimus()".

Best regards,

Lukas

>
> > 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.