[PATCH v4 1/3] drm/amd: Evict resources during PM ops prepare() callback

[Alex Deucher]

On Wed, Oct 4, 2023 at 1:37 PM Mario Limonciello
<mario.limonciello at amd.com> wrote:
>
> Linux PM core has a prepare() callback run before suspend.
>
> If the system is under high memory pressure, the resources may need
> to be evicted into swap instead.  If the storage backing for swap
> is offlined during the suspend() step then such a call may fail.
>
> So duplicate this step into prepare() to move evict majority of
> resources while leaving all existing steps that put the GPU into a
> low power state in suspend().
>
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2362
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  1 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 26 +++++++++++++++++++++-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    |  7 +++---
>  3 files changed, 30 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index d23fb4b5ad95..6643d0ed6b1b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1413,6 +1413,7 @@ void amdgpu_driver_postclose_kms(struct drm_device *dev,
>  void amdgpu_driver_release_kms(struct drm_device *dev);
>
>  int amdgpu_device_ip_suspend(struct amdgpu_device *adev);
> +int amdgpu_device_prepare(struct drm_device *dev);
>  int amdgpu_device_suspend(struct drm_device *dev, bool fbcon);
>  int amdgpu_device_resume(struct drm_device *dev, bool fbcon);
>  u32 amdgpu_get_vblank_counter_kms(struct drm_crtc *crtc);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index bad2b5577e96..67acee569c08 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -4259,6 +4259,31 @@ static int amdgpu_device_evict_resources(struct amdgpu_device *adev)
>  /*
>   * Suspend & resume.
>   */
> +/**
> + * amdgpu_device_prepare - prepare for device suspend
> + *
> + * @dev: drm dev pointer
> + *
> + * Prepare to put the hw in the suspend state (all asics).
> + * Returns 0 for success or an error on failure.
> + * Called at driver suspend.
> + */
> +int amdgpu_device_prepare(struct drm_device *dev)
> +{
> +       struct amdgpu_device *adev = drm_to_adev(dev);
> +       int r;
> +
> +       if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
> +               return 0;
> +
> +       /* Evict the majority of BOs before starting suspend sequence */
> +       r = amdgpu_device_evict_resources(adev);
> +       if (r)
> +               return r;
> +
> +       return 0;
> +}
> +
>  /**
>   * amdgpu_device_suspend - initiate device suspend
>   *
> @@ -4279,7 +4304,6 @@ int amdgpu_device_suspend(struct drm_device *dev, bool fbcon)
>
>         adev->in_suspend = true;
>
> -       /* Evict the majority of BOs before grabbing the full access */
>         r = amdgpu_device_evict_resources(adev);
>         if (r)
>                 return r;

Might want to add a note that this is likely a noop in the normal
suspend case and is just here to handle the case where
amdgpu_device_suspend() is called outside of the normal pmops
framework.
Other than that, the patch is:
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index e3471293846f..175167582db0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -2425,8 +2425,9 @@ static int amdgpu_pmops_prepare(struct device *dev)
>         /* Return a positive number here so
>          * DPM_FLAG_SMART_SUSPEND works properly
>          */
> -       if (amdgpu_device_supports_boco(drm_dev))
> -               return pm_runtime_suspended(dev);
> +       if (amdgpu_device_supports_boco(drm_dev) &&
> +           pm_runtime_suspended(dev))
> +               return 1;
>
>         /* if we will not support s3 or s2i for the device
>          *  then skip suspend
> @@ -2435,7 +2436,7 @@ static int amdgpu_pmops_prepare(struct device *dev)
>             !amdgpu_acpi_is_s3_active(adev))
>                 return 1;
>
> -       return 0;
> +       return amdgpu_device_prepare(drm_dev);
>  }
>
>  static void amdgpu_pmops_complete(struct device *dev)
> --
> 2.34.1
>