Re: [PATCH 13/15] platform/x86/amd/pmf: Add PMF-AMDGPU set interface

[Shyam Sundar S K <Shyam-sundar.S-k@amd.com>]

Hi Hans,

On 9/26/2023 4:05 PM, Hans de Goede wrote:
> Hi,
> 
> On 9/22/23 19:50, Shyam Sundar S K wrote:
>> For the Smart PC Solution to fully work, it has to enact to the actions
>> coming from TA. Add the initial code path for set interface to AMDGPU.
>>
>> Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
>> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_pmf.c | 21 +++++++++++++++++++++
>>  drivers/platform/x86/amd/pmf/pmf.h      |  2 ++
>>  drivers/platform/x86/amd/pmf/tee-if.c   | 19 +++++++++++++++++--
>>  include/linux/amd-pmf-io.h              |  1 +
>>  4 files changed, 41 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pmf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pmf.c
>> index 232d11833ddc..5c567bff0548 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pmf.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pmf.c
>> @@ -68,3 +68,24 @@ int amd_pmf_get_gfx_data(struct amd_gpu_pmf_data *pmf)
>>  	return 0;
>>  }
>>  EXPORT_SYMBOL_GPL(amd_pmf_get_gfx_data);
>> +
>> +int amd_pmf_set_gfx_data(struct amd_gpu_pmf_data *pmf)
>> +{
>> +	struct drm_device *drm_dev = pci_get_drvdata(pmf->gpu_dev);
>> +	struct amdgpu_device *adev = drm_to_adev(drm_dev);
>> +	struct backlight_device *bd;
>> +
>> +	if (!(adev->flags & AMD_IS_APU)) {
>> +		DRM_ERROR("PMF-AMDGPU interface not supported\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	bd = backlight_device_get_by_type(BACKLIGHT_RAW);
>> +	if (!bd)
>> +		return -ENODEV;
> 
> This assumes that the backlight is always controller by the amdgpu's
> native backlight driver, but it might e.g. also be handled by
> eacpi-video or by nvidia_wmi_ec_backlight (when using an AMD APU +
> nvidia dgpu).

PMF is meant for AMD APUs(atleast for now) and the _HID will only be
made visible if its AMD laptop. So using amdgpu's native BACKLIGHT_RAW
should be safe, right?

> 
> For now what should be done here is to call acpi_video_get_backlight_type()
> and then translate the return value from this into a backlight-type:
> 
>         acpi_backlight_video		-> BACKLIGHT_FIRMWARE
>         acpi_backlight_vendor,		-> BACKLIGHT_PLATFORM
>         acpi_backlight_native,		-> BACKLIGHT_RAW
>         acpi_backlight_nvidia_wmi_ec,	-> BACKLIGHT_FIRMWARE
>         acpi_backlight_apple_gmux,	-> BACKLIGHT_PLATFORM
> 

I can add this change in the v2, do you insist on this?

Thanks,
Shyam

> Also I'm worried about probe order here, this code currently assumes
> that the GPU or other backlight driver has loaded before this runs,
> which is not necessarily the case.
> 
> I think that if the backlight_device_get_by_type() fails this
> should be retried say every 10 seconds from some delayed workqueue
> for at least a couple of minutes after boot.
> 
> Regards,
> 
> Hans
> 
> 
> 
> 
>> +
>> +	backlight_device_set_brightness(bd, pmf->brightness);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(amd_pmf_set_gfx_data);
>> diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
>> index 9032df4ba48a..ce89cc0daa5a 100644
>> --- a/drivers/platform/x86/amd/pmf/pmf.h
>> +++ b/drivers/platform/x86/amd/pmf/pmf.h
>> @@ -73,6 +73,7 @@
>>  #define PMF_POLICY_STT_SKINTEMP_APU				7
>>  #define PMF_POLICY_STT_SKINTEMP_HS2				8
>>  #define PMF_POLICY_SYSTEM_STATE					9
>> +#define PMF_POLICY_DISPLAY_BRIGHTNESS				12
>>  #define PMF_POLICY_P3T						38
>>  
>>  /* TA macros */
>> @@ -480,6 +481,7 @@ enum ta_pmf_error_type {
>>  };
>>  
>>  struct pmf_action_table {
>> +	unsigned long display_brightness;
>>  	enum system_state system_state;
>>  	unsigned long spl; /* in mW */
>>  	unsigned long sppt; /* in mW */
>> diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
>> index 1608996654e8..eefffff83a4c 100644
>> --- a/drivers/platform/x86/amd/pmf/tee-if.c
>> +++ b/drivers/platform/x86/amd/pmf/tee-if.c
>> @@ -79,10 +79,10 @@ static int amd_pmf_update_uevents(struct amd_pmf_dev *dev, u16 event)
>>  	return 0;
>>  }
>>  
>> -static void amd_pmf_apply_policies(struct amd_pmf_dev *dev, struct ta_pmf_enact_result *out)
>> +static int amd_pmf_apply_policies(struct amd_pmf_dev *dev, struct ta_pmf_enact_result *out)
>>  {
>>  	u32 val, event = 0;
>> -	int idx;
>> +	int idx, ret;
>>  
>>  	for (idx = 0; idx < out->actions_count; idx++) {
>>  		val = out->actions_list[idx].value;
>> @@ -160,8 +160,23 @@ static void amd_pmf_apply_policies(struct amd_pmf_dev *dev, struct ta_pmf_enact_
>>  				dev->prev_data->system_state = 0;
>>  			}
>>  			break;
>> +
>> +		case PMF_POLICY_DISPLAY_BRIGHTNESS:
>> +			ret = amd_pmf_get_gfx_data(&dev->gfx_data);
>> +			if (ret)
>> +				return ret;
>> +
>> +			dev->prev_data->display_brightness = dev->gfx_data.brightness;
>> +			if (dev->prev_data->display_brightness != val) {
>> +				dev->gfx_data.brightness = val;
>> +				amd_pmf_set_gfx_data(&dev->gfx_data);
>> +				dev_dbg(dev->dev, "update DISPLAY_BRIGHTNESS : %d\n", val);
>> +			}
>> +			break;
>>  		}
>>  	}
>> +
>> +	return 0;
>>  }
>>  
>>  static int amd_pmf_invoke_cmd_enact(struct amd_pmf_dev *dev)
>> diff --git a/include/linux/amd-pmf-io.h b/include/linux/amd-pmf-io.h
>> index a2d4af231362..ecae387ddaa6 100644
>> --- a/include/linux/amd-pmf-io.h
>> +++ b/include/linux/amd-pmf-io.h
>> @@ -25,4 +25,5 @@ struct amd_gpu_pmf_data {
>>  };
>>  
>>  int amd_pmf_get_gfx_data(struct amd_gpu_pmf_data *pmf);
>> +int amd_pmf_set_gfx_data(struct amd_gpu_pmf_data *pmf);
>>  #endif
>