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

[Alex Deucher]

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?

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
>