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

From: Paul Menzel <pmenzel@molgen.mpg.de>
To: Richard Gong <richard.gong@amd.com>
Cc: mario.limonciello@amd.com, dri-devel@lists.freedesktop.org,
	amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	alexander.deucher@amd.com, christian.koenig@amd.com,
	xinhui.pan@amd.com, airlied@linux.ie, daniel@ffwll.ch
Subject: Re: [PATCHv2] drm/amdgpu: disable ASPM on Intel AlderLake based systems
Date: Sat, 9 Apr 2022 02:19:43 +0200	[thread overview]
Message-ID: <44354d78-b340-fbc4-fd6c-060d7ad3404e@molgen.mpg.de> (raw)
In-Reply-To: <20220408190502.4103670-1-richard.gong@amd.com>

Dear Richard,

Thank you for your patch.

Am 08.04.22 um 21:05 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 cannot be
> used with Intel AlderLake based systems to enable ASPM. Using these GFX

Alder Lake

> cards as video/display output, Intel Alder Lake based systems will hang
> during suspend/resume.

Please reflow for 75 characters per line.

Also please mention the exact system you had problems with (also 
firmware versions).

> 
> Add extra check to disable ASPM on Intel AlderLake based systems.

Is that a problem with Intel Alder Lake or the Dell system? Shouldn’t 
ASPM just be disabled for the problematic cards for the Dell system. You 
write newer cards worked fine.

> 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)

aspm

> +{
> +#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

Please do the check in C code and not the preprocessor.

> +}
> +
>   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 ||

Kind regards,

Paul