Re: [PATCHv2] drm/amdgpu: disable ASPM on Intel AlderLake based systems

["Lazar, Lijo" <lijo.lazar@amd.com>]

On 4/9/2022 12:35 AM, 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 cannot be
> used with Intel AlderLake based systems to enable ASPM. Using these GFX
> cards as video/display output, Intel Alder Lake based systems will hang
> during suspend/resume.
> 
> Add extra check to disable ASPM on Intel AlderLake based systems.
> 
> Fixes: 0064b0ce85bb ("drm/amd/pm: enable ASPM by default")
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1885
> Signed-off-by: Richard Gong <richard.gong@amd.com>
> ---
> 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..8b4eaf54b23e 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_64)
> +#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 intel_core_apsm_chk(void)

If this is only for Dell systems, use DMI_SYS_VENDOR/DMI_PRODUCT_NAME to 
identify the platform information from SMBIOS.

Better to rename to aspm_support_quirk_check() or similar, and return 
false on is_alderlake() or is_dell_xyz();

Thanks,
Lijo

> +{
> +#if IS_ENABLED(CONFIG_X86_64)
> +	struct cpuinfo_x86 *c = &cpu_data(0);
> +
> +	return (c->x86 == 6 && c->x86_model == INTEL_FAM6_ALDERLAKE);
> +#else
> +	return false;
> +#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) || intel_core_apsm_chk())
>   		return;
>   
>   	if (adev->flags & AMD_IS_APU ||
>