Re: [PATCHv4] drm/amdgpu: disable ASPM on Intel Alder Lake based systems

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

Hi Paul,

On 4/20/2022 3:29 PM, Paul Menzel wrote:
> 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.]
>
Not sure why, I am using Mozila Thunderbird for email. I am not using MS 
Outlook for upstream email.
>>>>>
>>>>> 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.

No, the system freeze then users have to recycle power to recover.

>
>>>>>> 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=05%7C01%7Crichard.gong%40amd.com%7Cce01de048c61456174ff08da230c750d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637860833680922036%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=vqhh3dTc%2FgBt7GrP9hKppWlrFy2F7DaivkNEuGekl0g%3D&amp;reserved=0
>
> Thank you Microsoft Outlook for keeping us safe. :(
I am not using MS Outlook for the email exchanges.
>
>>>>>>
>>>>>> 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?
those are pre-production Alder Lake based OEM systems
>
>> 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