[PATCH v4 5/5] drm/amdgpu: do not resume device in thaw for normal hibernation

[Rafael J. Wysocki]

On Wed, Jul 9, 2025 at 8:44 AM Samuel Zhang <guoqing.zhang at amd.com> wrote:
>
> For normal hibernation, GPU do not need to be resumed in thaw since it is
> not involved in writing the hibernation image. Skip resume in this case
> can reduce the hibernation time.
>
> On VM with 8 * 192GB VRAM dGPUs, 98% VRAM usage and 1.7TB system memory,
> this can save 50 minutes.
>
> Signed-off-by: Samuel Zhang <guoqing.zhang at amd.com>
> Reviewed-by: Lijo Lazar <lijo.lazar at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index 4f8632737574..c37285a8b2c5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -2541,6 +2541,10 @@ amdgpu_pci_shutdown(struct pci_dev *pdev)
>         if (amdgpu_ras_intr_triggered())
>                 return;
>
> +       /* device maybe not resumed here, return immediately in this case */
> +       if (adev->in_s4 && adev->in_suspend)
> +               return;
> +

You need to do analogous things in amdgpu_pmops_prepare() and
amdgpu_pmops_poweroff() AFAICS in case hibernation is carried out in
the "platform" mode.

>         /* if we are running in a VM, make sure the device
>          * torn down properly on reboot/shutdown.
>          * unfortunately we can't detect certain
> @@ -2654,8 +2658,17 @@ static int amdgpu_pmops_freeze(struct device *dev)
>  static int amdgpu_pmops_thaw(struct device *dev)
>  {
>         struct drm_device *drm_dev = dev_get_drvdata(dev);
> +       int event = pm_transition_event();
>
> -       return amdgpu_device_resume(drm_dev, true);
> +       switch (event) {
> +       case PM_EVENT_THAW: /* normal case */
> +               return 0;
> +       case PM_EVENT_RECOVER: /* error case */
> +               return amdgpu_device_resume(drm_dev, true);
> +       default:
> +               dev_err(dev, "unknown pm_transition_event %d\n", event);
> +               return -EOPNOTSUPP;
> +       }
>  }
>
>  static int amdgpu_pmops_poweroff(struct device *dev)
> --