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Message-ID: <efc1dfd1-2b54-aee5-1497-4b800a468141@molgen.mpg.de>
Date:   Wed, 20 Apr 2022 22:29:20 +0200
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Subject: Re: [PATCHv4] drm/amdgpu: disable ASPM on Intel Alder Lake based
 systems
Content-Language: en-US
To:     Richard Gong <richard.gong@amd.com>
Cc:     Alex Deucher <alexdeucher@gmail.com>,
        Dave Airlie <airlied@linux.ie>,
        Xinhui Pan <xinhui.pan@amd.com>,
        LKML <linux-kernel@vger.kernel.org>,
        dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org,
        Daniel Vetter <daniel@ffwll.ch>,
        Alexander Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        Mario Limonciello <mario.limonciello@amd.com>
References: <20220412215000.897344-1-richard.gong@amd.com>
 <d4ba3998-34aa-86d2-bde9-bc6ae9d8d08d@molgen.mpg.de>
 <CADnq5_MgvcGPWf2gYn_3qCr+Gq1P39tvv-W-o8NhivvMpMwUBA@mail.gmail.com>
 <91e916e3-d793-b814-6cbf-abee0667f5f8@molgen.mpg.de>
 <94fd858d-1792-9c05-b5c6-1b028427687d@amd.com>
From:   Paul Menzel <pmenzel@molgen.mpg.de>
In-Reply-To: <94fd858d-1792-9c05-b5c6-1b028427687d@amd.com>
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Dear Richard,


Am 19.04.22 um 23:46 schrieb Gong, Richard:

> On 4/14/2022 2:52 AM, Paul Menzel wrote:
>> [Cc: -kernel test robot <lkp@intel.com>]

[…]

>> Am 13.04.22 um 15:00 schrieb Alex Deucher:
>>> On Wed, Apr 13, 2022 at 3:43 AM Paul Menzel wrote:
>>
>>>> Thank you for sending out v4.
>>>>
>>>> Am 12.04.22 um 23:50 schrieb Richard Gong:
>>>>> Active State Power Management (ASPM) feature is enabled since 
>>>>> kernel 5.14.
>>>>> There are some AMD GFX cards (such as WX3200 and RX640) that won't 
>>>>> work
>>>>> with ASPM-enabled Intel Alder Lake based systems. Using these GFX 
>>>>> cards as
>>>>> video/display output, Intel Alder Lake based systems will hang during
>>>>> suspend/resume.

[Your email program wraps lines in cited text for some reason, making 
the citation harder to read.]

>>>>
>>>> I am still not clear, what “hang during suspend/resume” means. I guess
>>>> suspending works fine? During resume (S3 or S0ix?), where does it hang?
>>>> The system is functional, but there are only display problems?
> System freeze after suspend/resume.

But you see certain messages still? At what point does it freeze 
exactly? In the bug report you posted Linux messages.

>>>>> The issue was initially reported on one system (Dell Precision 3660 
>>>>> with
>>>>> BIOS version 0.14.81), but was later confirmed to affect at least 4 
>>>>> Alder
>>>>> Lake based systems.
>>>>>
>>>>> Add extra check to disable ASPM on Intel Alder Lake based systems.
>>>>>
>>>>> Fixes: 0064b0ce85bb ("drm/amd/pm: enable ASPM by default")
>>>>> 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%7Ce7febed5d6a441c3a58008da1debb99c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637855195670542145%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=7cEnE%2BSM9e5IGFxSLloCLtCOxovBpaPz0Ns0Ta2vVlc%3D&amp;reserved=0

Thank you Microsoft Outlook for keeping us safe. :(

>>>>>
>>>>> Reported-by: kernel test robot <lkp@intel.com>
>>>>
>>>> This tag is a little confusing. Maybe clarify that it was for an issue
>>>> in a previous patch iteration?
> 
> I did describe in change-list version 3 below, which corrected the build 
> error with W=1 option.
> 
> It is not good idea to add the description for that to the commit 
> message, this is why I add descriptions on change-list version 3.

Do as you wish, but the current style is confusing, and readers of the 
commit are going to think, the kernel test robot reported the problem 
with AMD VI ASICs and Intel Alder Lake systems.

>>>>
>>>>> Signed-off-by: Richard Gong <richard.gong@amd.com>
>>>>> ---
>>>>> v4: s/CONFIG_X86_64/CONFIG_X86
>>>>>       enhanced check logic
>>>>> v3: s/intel_core_asom_chk/aspm_support_quirk_check
>>>>>       correct build error with W=1 option
>>>>> v2: correct commit description
>>>>>       move the check from chip family to problematic platform
>>>>> ---
>>>>>    drivers/gpu/drm/amd/amdgpu/vi.c | 17 ++++++++++++++++-
>>>>>    1 file changed, 16 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/vi.c 
>>>>> b/drivers/gpu/drm/amd/amdgpu/vi.c
>>>>> index 039b90cdc3bc..b33e0a9bee65 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/vi.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/vi.c
>>>>> @@ -81,6 +81,10 @@
>>>>>    #include "mxgpu_vi.h"
>>>>>    #include "amdgpu_dm.h"
>>>>>
>>>>> +#if IS_ENABLED(CONFIG_X86)
>>>>> +#include <asm/intel-family.h>
>>>>> +#endif
>>>>> +
>>>>>    #define ixPCIE_LC_L1_PM_SUBSTATE    0x100100C6
>>>>>    #define PCIE_LC_L1_PM_SUBSTATE__LC_L1_SUBSTATES_OVERRIDE_EN_MASK 
>>>>> 0x00000001L
>>>>>    #define PCIE_LC_L1_PM_SUBSTATE__LC_PCI_PM_L1_2_OVERRIDE_MASK 
>>>>> 0x00000002L
>>>>> @@ -1134,13 +1138,24 @@ static void vi_enable_aspm(struct 
>>>>> amdgpu_device *adev)
>>>>>                WREG32_PCIE(ixPCIE_LC_CNTL, data);
>>>>>    }
>>>>>
>>>>> +static bool aspm_support_quirk_check(void)
>>>>> +{
>>>>> +     if (IS_ENABLED(CONFIG_X86)) {
>>>>> +             struct cpuinfo_x86 *c = &cpu_data(0);
>>>>> +
>>>>> +             return !(c->x86 == 6 && c->x86_model == 
>>>>> INTEL_FAM6_ALDERLAKE);
>>>>> +     }
>>>>> +
>>>>> +     return true;
>>>>> +}
>>>>> +
>>>>>    static void vi_program_aspm(struct amdgpu_device *adev)
>>>>>    {
>>>>>        u32 data, data1, orig;
>>>>>        bool bL1SS = false;
>>>>>        bool bClkReqSupport = true;
>>>>>
>>>>> -     if (!amdgpu_device_should_use_aspm(adev))
>>>>> +     if (!amdgpu_device_should_use_aspm(adev) || 
>>>>> !aspm_support_quirk_check())
>>>>>                return;
>>>>
>>>> Can users still forcefully enable ASPM with the parameter 
>>>> `amdgpu.aspm`?
>>>>
> As Mario mentioned in a separate reply, we can't forcefully enable ASPM 
> with the parameter 'amdgpu.aspm'.

That would be a regression on systems where ASPM used to work. Hmm. I 
guess, you could say, there are no such systems.

>>>>>
>>>>>        if (adev->flags & AMD_IS_APU ||
>>>>
>>>> If I remember correctly, there were also newer cards, where ASPM worked
>>>> with Intel Alder Lake, right? Can only the problematic generations for
>>>> WX3200 and RX640 be excluded from ASPM?
>>>
>>> This patch only disables it for the generatioaon that was problematic.
>>
>> Could that please be made clear in the commit message summary, and 
>> message?
> 
> Are you ok with the commit messages below?

Please change the commit message summary. Maybe:

drm/amdgpu: VI: Disable ASPM on Intel Alder Lake based systems

> Active State Power Management (ASPM) feature is enabled since kernel 5.14.
> 
> There are some AMD GFX cards (such as WX3200 and RX640) that won't work
> with ASPM-enabled Intel Alder Lake based systems. Using these GFX cards as
> video/display output, Intel Alder Lake based systems will freeze after
> suspend/resume.

Something like:

On Intel Alder Lake based systems using ASPM with AMD GFX Volcanic 
Islands (VI) cards, like WX3200 and RX640, graphics don’t initialize 
when resuming from S0ix(?).


> The issue was initially reported on one system (Dell Precision 3660 with
> BIOS version 0.14.81), but was later confirmed to affect at least 4 Alder
> Lake based systems.

Which ones?

> Add extra check to disable ASPM on Intel Alder Lake based systems with
> problematic generation GFX cards.

… with the problematic Volcanic Islands GFX cards.

>>
>> Loosely related, is there a public (or internal issue) to analyze how 
>> to get ASPM working for VI generation devices with Intel Alder Lake?
> 
> As Alex mentioned, we need support from Intel. We don't have any update 
> on that.

It’d be great to get that fixed properly.

Last thing, please don’t hate me, does Linux log, that ASPM is disabled?


Kind regards,

Paul