linux-kernel - Re: [PATCHv5] drm/amdgpu: vi: disable ASPM on Intel Alder Lake based systems

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Date:   Sun, 1 May 2022 09:14:32 +0200
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Richard Gong <richard.gong@....com>
Cc:     alexander.deucher@....com, christian.koenig@....com,
        xinhui.pan@....com, airlied@...ux.ie, daniel@...ll.ch,
        amd-gfx@...ts.freedesktop.org, kernel test robot <lkp@...el.com>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        mario.limonciello@....com
Subject: Re: [PATCHv5] drm/amdgpu: vi: disable ASPM on Intel Alder Lake based
 systems

Dear Richard,


Am 29.04.22 um 18:06 schrieb Richard Gong:
> Active State Power Management (ASPM) feature is enabled since kernel 5.14.
> There are some AMD Volcanic Islands (VI) GFX cards, such as the WX3200 and
> RX640, that do not 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.

As replied in v4 just now, “freeze” is misleading if you can still run 
`dmesg` after resume.


Kind regards,

Paul


> The issue was originally reported on one system (Dell Precision 3660 with
> BIOS version 0.14.81), but was later confirmed to affect at least 4
> pre-production Alder Lake based systems.
> 
> Add an extra check to disable ASPM on Intel Alder Lake based systems with
> the problematic AMD Volcanic Islands GFX cards.
> 
> Fixes: 0064b0ce85bb ("drm/amd/pm: enable ASPM by default")
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1885
> Reported-by: kernel test robot <lkp@...el.com>
> Signed-off-by: Richard Gong <richard.gong@....com>
> ---
> v5: added vi to commit header and updated commit message
>      rolled back guard with the preprocessor as did in v2 to correct build
>      error on non-x86 systems
> v4: s/CONFIG_X86_64/CONFIG_X86
>      enhanced check logic
> v3: s/intel_core_aspm_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..45f0188c4273 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);
> +#else
> +	return true;
> +#endif
> +}
> +
>   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;
>   
>   	if (adev->flags & AMD_IS_APU ||