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

[Alex Deucher <alexdeucher@gmail.com>]

On Wed, Apr 13, 2022 at 3:43 AM Paul Menzel <pmenzel@molgen.mpg.de> wrote:
>
> Dear Richard,
>
>
> 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.
>
> 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?
>
> > 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://gitlab.freedesktop.org/drm/amd/-/issues/1885
> > 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?
>
> > 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`?
>
> >
> >       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 generation that was problematic.

Alex

>
>
> Kind regards,
>
> Paul