[PATCH] drm/amd: Add a sysfs file to detect whether a GPU is an APU

[Mario Limonciello]

On 6/16/25 9:53 PM, Alex Deucher wrote:
> On Mon, Jun 16, 2025 at 4:21 PM Mario Limonciello <superm1 at kernel.org> wrote:
>>
>> From: Mario Limonciello <mario.limonciello at amd.com>
>>
>> In order to discover whether a GPU is part of a dGPU or APU userspace has
>> to do some mental gymnastics or heuristics.  Add a sysfs file that clearly
>> indicates to userspace.
> 
> You can already query this via the INFO IOCTL.  What use case did you
> have in mind for this interface?

You're right; the IOCTL is totally fine for this.  Disregard the patch.

Thanks,>
> Alex
> 
>>
>> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
>> ---
>>   drivers/gpu/drm/amd/pm/amdgpu_pm.c     | 16 ++++++++++++++++
>>   drivers/gpu/drm/amd/pm/inc/amdgpu_pm.h |  1 +
>>   2 files changed, 17 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
>> index edd9895b46c02..4e4c77488e334 100644
>> --- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c
>> +++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
>> @@ -945,6 +945,21 @@ static ssize_t amdgpu_get_pp_features(struct device *dev,
>>          return size;
>>   }
>>
>> +/**
>> + * DOC: apu
>> + *
>> + * Represents whether GPU is on a dGPU (0) or APU (1)
>> + */
>> +static ssize_t amdgpu_get_apu(struct device *dev,
>> +                             struct device_attribute *attr,
>> +                             char *buf)
>> +{
>> +       struct drm_device *ddev = dev_get_drvdata(dev);
>> +       struct amdgpu_device *adev = drm_to_adev(ddev);
>> +
>> +       return sysfs_emit(buf, "%d\n", adev->flags & AMD_IS_APU ? 1 : 0);
>> +}
>> +
>>   /**
>>    * DOC: pp_dpm_sclk pp_dpm_mclk pp_dpm_socclk pp_dpm_fclk pp_dpm_dcefclk pp_dpm_pcie
>>    *
>> @@ -2287,6 +2302,7 @@ static struct amdgpu_device_attr amdgpu_device_attrs[] = {
>>                                .attr_update = ss_bias_attr_update),
>>          AMDGPU_DEVICE_ATTR_RO(pm_metrics,                               ATTR_FLAG_BASIC,
>>                                .attr_update = amdgpu_pm_metrics_attr_update),
>> +       AMDGPU_DEVICE_ATTR_RO(apu,                                      ATTR_FLAG_BASIC),
>>   };
>>
>>   static int default_attr_update(struct amdgpu_device *adev, struct amdgpu_device_attr *attr,
>> diff --git a/drivers/gpu/drm/amd/pm/inc/amdgpu_pm.h b/drivers/gpu/drm/amd/pm/inc/amdgpu_pm.h
>> index c12ced32f7808..ffd008c1e6ec2 100644
>> --- a/drivers/gpu/drm/amd/pm/inc/amdgpu_pm.h
>> +++ b/drivers/gpu/drm/amd/pm/inc/amdgpu_pm.h
>> @@ -78,6 +78,7 @@ enum amdgpu_device_attr_id {
>>          device_attr_id__smartshift_dgpu_power,
>>          device_attr_id__smartshift_bias,
>>          device_attr_id__pm_metrics,
>> +       device_attr_id__apu,
>>          device_attr_id__count,
>>   };
>>
>> --
>> 2.43.0
>>