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Date:   Wed, 13 Apr 2022 08:40:28 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Richard Gong <richard.gong@amd.com>
Cc:     alexander.deucher@amd.com, christian.koenig@amd.com,
        xinhui.pan@amd.com, airlied@linux.ie, daniel@ffwll.ch,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, mario.limonciello@amd.com,
        kernel test robot <lkp@intel.com>
Subject: Re: [PATCHv4] drm/amdgpu: disable ASPM on Intel Alder Lake based
 systems
Message-ID: <Ylbu7OGHVaqnznQb@thelio-3990X>
References: <20220412215000.897344-1-richard.gong@amd.com>
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In-Reply-To: <20220412215000.897344-1-richard.gong@amd.com>
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Hi Richard,

On Tue, Apr 12, 2022 at 04:50:00PM -0500, Richard Gong wrote:
> 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.
> 
> 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>
> 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);
> +	}

I have not seen this reported by a bot, sorry if it is a duplicate. This
breaks non-x86 builds (arm64 allmodconfig for example):

drivers/gpu/drm/amd/amdgpu/vi.c:1144:28: error: implicit declaration of function 'cpu_data' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
                struct cpuinfo_x86 *c = &cpu_data(0);
                                         ^
drivers/gpu/drm/amd/amdgpu/vi.c:1144:27: error: cannot take the address of an rvalue of type 'int'
                struct cpuinfo_x86 *c = &cpu_data(0);
                                        ^~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/vi.c:1146:13: error: incomplete definition of type 'struct cpuinfo_x86'
                return !(c->x86 == 6 && c->x86_model == INTEL_FAM6_ALDERLAKE);
                         ~^
drivers/gpu/drm/amd/amdgpu/vi.c:1144:10: note: forward declaration of 'struct cpuinfo_x86'
                struct cpuinfo_x86 *c = &cpu_data(0);
                       ^
drivers/gpu/drm/amd/amdgpu/vi.c:1146:28: error: incomplete definition of type 'struct cpuinfo_x86'
                return !(c->x86 == 6 && c->x86_model == INTEL_FAM6_ALDERLAKE);
                                        ~^
drivers/gpu/drm/amd/amdgpu/vi.c:1144:10: note: forward declaration of 'struct cpuinfo_x86'
                struct cpuinfo_x86 *c = &cpu_data(0);
                       ^
drivers/gpu/drm/amd/amdgpu/vi.c:1146:43: error: use of undeclared identifier 'INTEL_FAM6_ALDERLAKE'
                return !(c->x86 == 6 && c->x86_model == INTEL_FAM6_ALDERLAKE);
                                                        ^
5 errors generated.

'struct cpuinfo_x86' is only defined for CONFIG_X86 so this section
needs to guarded with the preprocessor, which is how it was done in v2.
Please go back to that.

Cheers,
Nathan