[PATCH] drm/amdgpu: don't runtime suspend if there are displays attached (v2)

[Alex Deucher]

Should be v3, fixed locally.

Alex

On Wed, Apr 20, 2022 at 11:16 PM Alex Deucher <alexander.deucher at amd.com> wrote:
>
> We normally runtime suspend when there are displays attached if they
> are in the DPMS off state, however, if something wakes the GPU
> we send a hotplug event on resume (in case any displays were connected
> while the GPU was in suspend) which can cause userspace to light
> up the displays again soon after they were turned off.
>
> Prior to
> commit 087451f372bf76 ("drm/amdgpu: use generic fb helpers instead of setting up AMD own's."),
> the driver took a runtime pm reference when the fbdev emulation was
> enabled because we didn't implement proper shadowing support for
> vram access when the device was off so the device never runtime
> suspended when there was a console bound.  Once that commit landed,
> we now utilize the core fb helper implementation which properly
> handles the emulation, so runtime pm now suspends in cases where it did
> not before.  Ultimately, we need to sort out why runtime suspend in not
> working in this case for some users, but this should restore similar
> behavior to before.
>
> v2: move check into runtime_suspend
> v3: wake ups -> wakeups in comment, retain pm_runtime behavior in
>     runtime_idle callback
>
> Fixes: 087451f372bf76 ("drm/amdgpu: use generic fb helpers instead of setting up AMD own's.")
> Tested-by: Michele Ballabio <ballabio.m at gmail.com>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 105 ++++++++++++++++--------
>  1 file changed, 70 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index 4efaa183abcd..ebd37fb19cdb 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -2395,6 +2395,71 @@ static int amdgpu_pmops_restore(struct device *dev)
>         return amdgpu_device_resume(drm_dev, true);
>  }
>
> +static int amdgpu_runtime_idle_check_display(struct device *dev)
> +{
> +       struct pci_dev *pdev = to_pci_dev(dev);
> +       struct drm_device *drm_dev = pci_get_drvdata(pdev);
> +       struct amdgpu_device *adev = drm_to_adev(drm_dev);
> +
> +       if (adev->mode_info.num_crtc) {
> +               struct drm_connector *list_connector;
> +               struct drm_connector_list_iter iter;
> +               int ret = 0;
> +
> +               /* XXX: Return busy if any displays are connected to avoid
> +                * possible display wakeups after runtime resume due to
> +                * hotplug events in case any displays were connected while
> +                * the GPU was in suspend.  Remove this once that is fixed.
> +                */
> +               mutex_lock(&drm_dev->mode_config.mutex);
> +               drm_connector_list_iter_begin(drm_dev, &iter);
> +               drm_for_each_connector_iter(list_connector, &iter) {
> +                       if (list_connector->status == connector_status_connected) {
> +                               ret = -EBUSY;
> +                               break;
> +                       }
> +               }
> +               drm_connector_list_iter_end(&iter);
> +               mutex_unlock(&drm_dev->mode_config.mutex);
> +
> +               if (ret)
> +                       return ret;
> +
> +               if (amdgpu_device_has_dc_support(adev)) {
> +                       struct drm_crtc *crtc;
> +
> +                       drm_for_each_crtc(crtc, drm_dev) {
> +                               drm_modeset_lock(&crtc->mutex, NULL);
> +                               if (crtc->state->active)
> +                                       ret = -EBUSY;
> +                               drm_modeset_unlock(&crtc->mutex);
> +                               if (ret < 0)
> +                                       break;
> +                       }
> +               } else {
> +                       mutex_lock(&drm_dev->mode_config.mutex);
> +                       drm_modeset_lock(&drm_dev->mode_config.connection_mutex, NULL);
> +
> +                       drm_connector_list_iter_begin(drm_dev, &iter);
> +                       drm_for_each_connector_iter(list_connector, &iter) {
> +                               if (list_connector->dpms ==  DRM_MODE_DPMS_ON) {
> +                                       ret = -EBUSY;
> +                                       break;
> +                               }
> +                       }
> +
> +                       drm_connector_list_iter_end(&iter);
> +
> +                       drm_modeset_unlock(&drm_dev->mode_config.connection_mutex);
> +                       mutex_unlock(&drm_dev->mode_config.mutex);
> +               }
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       return 0;
> +}
> +
>  static int amdgpu_pmops_runtime_suspend(struct device *dev)
>  {
>         struct pci_dev *pdev = to_pci_dev(dev);
> @@ -2407,6 +2472,10 @@ static int amdgpu_pmops_runtime_suspend(struct device *dev)
>                 return -EBUSY;
>         }
>
> +       ret = amdgpu_runtime_idle_check_display(dev);
> +       if (ret)
> +               return ret;
> +
>         /* wait for all rings to drain before suspending */
>         for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
>                 struct amdgpu_ring *ring = adev->rings[i];
> @@ -2516,41 +2585,7 @@ static int amdgpu_pmops_runtime_idle(struct device *dev)
>                 return -EBUSY;
>         }
>
> -       if (amdgpu_device_has_dc_support(adev)) {
> -               struct drm_crtc *crtc;
> -
> -               drm_for_each_crtc(crtc, drm_dev) {
> -                       drm_modeset_lock(&crtc->mutex, NULL);
> -                       if (crtc->state->active)
> -                               ret = -EBUSY;
> -                       drm_modeset_unlock(&crtc->mutex);
> -                       if (ret < 0)
> -                               break;
> -               }
> -
> -       } else {
> -               struct drm_connector *list_connector;
> -               struct drm_connector_list_iter iter;
> -
> -               mutex_lock(&drm_dev->mode_config.mutex);
> -               drm_modeset_lock(&drm_dev->mode_config.connection_mutex, NULL);
> -
> -               drm_connector_list_iter_begin(drm_dev, &iter);
> -               drm_for_each_connector_iter(list_connector, &iter) {
> -                       if (list_connector->dpms ==  DRM_MODE_DPMS_ON) {
> -                               ret = -EBUSY;
> -                               break;
> -                       }
> -               }
> -
> -               drm_connector_list_iter_end(&iter);
> -
> -               drm_modeset_unlock(&drm_dev->mode_config.connection_mutex);
> -               mutex_unlock(&drm_dev->mode_config.mutex);
> -       }
> -
> -       if (ret == -EBUSY)
> -               DRM_DEBUG_DRIVER("failing to power off - crtc active\n");
> +       ret = amdgpu_runtime_idle_check_display(dev);
>
>         pm_runtime_mark_last_busy(dev);
>         pm_runtime_autosuspend(dev);
> --
> 2.35.1
>