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

[Gong, Richard]

Hi Alex,

On 4/8/2022 10:54 AM, Alex Deucher wrote:
> 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.

I thought that initially.

But I found out that suspend/resume works just fine on the "problematic" 
platform (Dell Precision 3660, Intel ADL based) + AMD W6400 GFX card. 
With WX3200 or RX640, suspend/resume works only when ASPM was disabled. 
Both WX3200 and RX640 are from CHIP_POLARIS12 family.

This is why I take chip family approach.

Regards,

Richard

> Alex
>
> > > Signed-off-by: Richard Gong <richard.gong@xxxxxxx>
> > > Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.freedesktop.org%2Fdrm%2Famd%2F-%2Fissues%2F1885&amp;data=04%7C01%7CRichard.Gong%40amd.com%7C96f8f686f75f43abb5ed08da19780fab%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637850300760921285%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=xVKC0Q16ho5Y2GDuN%2Fnx68wm6NzOIyR5xJbiXPgqPpQ%3D&amp;reserved=0
> > > ---
> > >   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