Message-ID: <462dce7d-73fc-ea8c-0a8a-5e8722ee1967@molgen.mpg.de>
Date:   Wed, 20 Apr 2022 23:02:27 +0200
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Richard Gong <richard.gong@....com>
Cc:     Alex Deucher <alexdeucher@...il.com>,
        Dave Airlie <airlied@...ux.ie>,
        Xinhui Pan <xinhui.pan@....com>,
        LKML <linux-kernel@...r.kernel.org>,
        dri-devel@...ts.freedesktop.org, amd-gfx@...ts.freedesktop.org,
        Daniel Vetter <daniel@...ll.ch>,
        Alexander Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCHv4] drm/amdgpu: disable ASPM on Intel Alder Lake based
 systems

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@...gen.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@...el.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%7C487aaa63098b462e146a08da230f2319%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637860845178176835%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=3IVldn05qNa2XVp1Lu58SriS8k9mk4U9K9p3F3IYPe0%3D&amp;reserved=0 
>>>>>>>>>
>>>>
>>>> Thank you Microsoft Outlook for keeping us safe. :(
>>>>
>>>>>>>>>
>>>>>>>>> Reported-by: kernel test robot <lkp@...el.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@....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:

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


Kind regards,

Paul

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