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

["Gong, Richard" <richard.gong@amd.com>]

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@amd.com> wrote:
>> [Public]
>>
>>
>>
>>> -----Original Message-----
>>> From: Gong, Richard <Richard.Gong@amd.com>
>>> Sent: Friday, April 8, 2022 10:45
>>> To: Deucher, Alexander <Alexander.Deucher@amd.com>; Koenig, Christian
>>> <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>;
>>> airlied@linux.ie; daniel@ffwll.ch
>>> Cc: amd-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org; linux-
>>> kernel@vger.kernel.org; Limonciello, Mario <Mario.Limonciello@amd.com>;
>>> Gong, Richard <Richard.Gong@amd.com>
>>> 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@amd.com>
>>> 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