Re: [PATCH] drm/amdgpu: disable ASPM for legacy products that don't support ASPM

[Alex Deucher]

On Fri, Apr 8, 2022 at 11:47 AM Limonciello, Mario
<Mario.Limonciello@xxxxxxx> wrote:
>
> [Public]
>
>
>
> > -----Original Message-----
> > From: Gong, Richard <Richard.Gong@xxxxxxx>
> > Sent: Friday, April 8, 2022 10:45
> > To: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Koenig, Christian
> > <Christian.Koenig@xxxxxxx>; Pan, Xinhui <Xinhui.Pan@xxxxxxx>;
> > airlied@xxxxxxxx; daniel@xxxxxxxx
> > Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-
> > kernel@xxxxxxxxxxxxxxx; Limonciello, Mario <Mario.Limonciello@xxxxxxx>;
> > Gong, Richard <Richard.Gong@xxxxxxx>
> > Subject: [PATCH] drm/amdgpu: disable ASPM for legacy products that don't
> > support ASPM
> >
> > Active State Power Management (ASPM) feature is enabled since kernel
> > 5.14.
> > However there are some legacy products (WX3200 and RX640 are examples)
> > that
> > do not support ASPM. Use them as video/display output and system would
> > hang
> > during suspend/resume.
> >
> > Add extra check to disable ASPM for old products that don't have
> > ASPM support.

The patch description is incorrect.  ASPM works just fine on these
GPUs.  It's more of an issue with whether the underlying platform
supports ASPM or not.  Rather than disabling a chip family, I would
prefer to add a check for problematic platforms and disable ASPM on
those platforms.

Alex

> >
> > Signed-off-by: Richard Gong <richard.gong@xxxxxxx>
> > Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1885
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> > index bb1c025d9001..8987107f41ee 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> > @@ -2012,6 +2012,10 @@ static int amdgpu_pci_probe(struct pci_dev
> > *pdev,
> >       if (amdgpu_aspm == -1 && !pcie_aspm_enabled(pdev))
> >               amdgpu_aspm = 0;
> >
> > +     /* disable ASPM for the legacy products that don't support ASPM */
> > +     if ((flags & AMD_ASIC_MASK) == CHIP_POLARIS12)
> > +             amdgpu_aspm = 0;
> > +
>
> I think it's problematic to disable it for the entire driver.  There might be multiple
> AMDGPUs in the system, and others may support ASPM.
>
> Can it be done just as part of probe for Polaris?
>
> >       if (amdgpu_virtual_display ||
> >           amdgpu_device_asic_has_dc_support(flags & AMD_ASIC_MASK))
> >               supports_atomic = true;
> > --
> > 2.25.1