Re: [PATCH] drm/amdgpu: Add a new module param to disable d3cold

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

On 11/30/2023 11:59 AM, Ma, Jun wrote:
> Hi Alex,
> 
> On 11/30/2023 12:39 AM, Alex Deucher wrote:
>> On Wed, Nov 29, 2023 at 11:37 AM Ma Jun <Jun.Ma2@amd.com> wrote:
>>>
>>> Some platforms can't resume from d3cold state, So add a
>>> new module parameter to disable d3cold state for debugging
>>> purpose or workaround.
>>
>> Doesn't the runpm parameter already handle this?  If you set runpm=0,
>> that should disable d3cold.
>>
> runpm=0  prevents calls to driver runtime_suspend/resume functions.
> While d3cold=0 allows calls to runtime_suspend/resume functions and puts
> the device in d3hot state instead of d3cold.
> 

Why not use the sysfs node to change "d3cold_allowed" on the device's 
upstream bridge?

Thanks,
Lijo

> Regards,
> Ma Jun
> 
>> Alex
>>
>>>
>>> Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h        | 1 +
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 7 +++++++
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    | 8 ++++++++
>>>   3 files changed, 16 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>> index a9f54df9d33e..db9f60790267 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>> @@ -166,6 +166,7 @@ extern char amdgpu_lockup_timeout[AMDGPU_MAX_TIMEOUT_PARAM_LENGTH];
>>>   extern int amdgpu_dpm;
>>>   extern int amdgpu_fw_load_type;
>>>   extern int amdgpu_aspm;
>>> +extern int amdgpu_d3cold;
>>>   extern int amdgpu_runtime_pm;
>>>   extern uint amdgpu_ip_block_mask;
>>>   extern int amdgpu_bapm;
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> index 22b6a910b7f2..90501c44e7d0 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> @@ -264,6 +264,13 @@ bool amdgpu_device_supports_px(struct drm_device *dev)
>>>   bool amdgpu_device_supports_boco(struct drm_device *dev)
>>>   {
>>>          struct amdgpu_device *adev = drm_to_adev(dev);
>>> +       struct pci_dev *parent;
>>> +
>>> +       if (!amdgpu_d3cold) {
>>> +               parent = pcie_find_root_port(adev->pdev);
>>> +               pci_d3cold_disable(parent);
>>> +               return false;
>>> +       }
>>>
>>>          if (adev->has_pr3 ||
>>>              ((adev->flags & AMD_IS_PX) && amdgpu_is_atpx_hybrid()))
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> index 5f14f04cb553..c9fbb8bd4169 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> @@ -145,6 +145,7 @@ char amdgpu_lockup_timeout[AMDGPU_MAX_TIMEOUT_PARAM_LENGTH];
>>>   int amdgpu_dpm = -1;
>>>   int amdgpu_fw_load_type = -1;
>>>   int amdgpu_aspm = -1;
>>> +int amdgpu_d3cold = -1;
>>>   int amdgpu_runtime_pm = -1;
>>>   uint amdgpu_ip_block_mask = 0xffffffff;
>>>   int amdgpu_bapm = -1;
>>> @@ -359,6 +360,13 @@ module_param_named(fw_load_type, amdgpu_fw_load_type, int, 0444);
>>>   MODULE_PARM_DESC(aspm, "ASPM support (1 = enable, 0 = disable, -1 = auto)");
>>>   module_param_named(aspm, amdgpu_aspm, int, 0444);
>>>
>>> +/**
>>> + * DOC: d3cold (int)
>>> + * To disable d3cold (1 = enable, 0 = disable). The default is -1 (auto, enabled).
>>> + */
>>> +MODULE_PARM_DESC(d3cold, "d3cold support (1 = enable, 0 = disable, -1 = auto)");
>>> +module_param_named(d3cold, amdgpu_d3cold, int, 0444);
>>> +
>>>   /**
>>>    * DOC: runpm (int)
>>>    * Override for runtime power management control for dGPUs. The amdgpu driver can dynamically power down
>>> --
>>> 2.34.1
>>>