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

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

On 4/20/2022 4:02 PM, Paul Menzel wrote:
> Dear Richard,
>
>
> Am 20.04.22 um 22:56 schrieb Gong, Richard:
>
>> On 4/20/2022 3:48 PM, Paul Menzel wrote:
>
>>> Am 20.04.22 um 22:40 schrieb Alex Deucher:
>>>> On Wed, Apr 20, 2022 at 4:29 PM Paul Menzel <pmenzel@molgen.mpg.de> 
>>>> wrote:
>>>
>>>>> 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=05%7C01%7Crichard.gong%40amd.com%7C509e0378edcf477605a708da231114f0%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637860853537880384%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=SoXDKGHUiiQN4rcL7FpCotouWFt0kkAbcHyO3esfNlE%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?
>>>>
>>>> I'm not sure what gets logged at the platform level with respect to
>>>> ASPM, but whether or not the driver enables ASPM is tied to whether
>>>> ASPM is allowed at the platform level or not so if the platform
>>>> indicates that ASPM is not supported, the driver won't enable it.  The
>>>> driver does not log whether ASPM is enabled or not if that is what you
>>>> are asking.  As to whether or not it should, it comes down to how much
>>>> stuff is worth indiciating in the log.  The driver is already pretty
>>>> chatty by driver standards.
>>>
>>> I specifically mean, Linux should log the quirks it applies. (As a 
>>> normal user, I’d also expect ASPM to work nowadays, so a message, 
>>> that it’s disabled would help a lot.)
>>
>> In general rule we shouldn't generate additional log unless something 
>> went wrong with the system.
>
> Please run `dmesg` and see that your statement is false. That’s what 
> log levels are for, and in your case, it would be at least error 
> level. Also, I claim, something indeed went wrong, because a quirk had 
> to be applied. So please add a notice log level, that ASPM gets disabled:

 From my previous experience with upstream, the maintainers simply don't 
like adding logs unless absolutely need.

I can add a pr_warn or dev_warn, but I can't guarantee that maintainers 
will take that in my case.

>
> Disable ASPM on Alder Lake with Volcanic Islands card due to resume 
> problems. System energy consumption might be higher than expected.
>
>
> Kind regards,
>
> Paul