Re: [PATCH 2/4] drm/msm: Cut dpu_kms hooks from msm_pm_suspend/resume

[Sean Paul <sean-p7yTbzM4H96eqtR555YLDQ@public.gmane.org>]

On Fri, Oct 05, 2018 at 11:48:41AM -0400, Bruce Wang wrote:
> Removes the traces of the non-atomic helper calls in
> msm_pm_suspend/resume since we just deleted those functions (see patch
> 1). Also removes the drm_kms_helper_poll_disable/enable calls, since
> the DRM_CONNECTOR_POLL_CONNECT flag is never set so periodic polling
> doesn't happen anyways.
> 
> Signed-off-by: Bruce Wang <bzwang@chromium.org>
> ---
>  drivers/gpu/drm/msm/msm_drv.c | 28 ++++++++++------------------
>  drivers/gpu/drm/msm/msm_kms.h |  3 ---
>  2 files changed, 10 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index 4904d0d41409..f987df7f10df 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -1069,37 +1069,29 @@ static int msm_pm_suspend(struct device *dev)
>  {
>  	struct drm_device *ddev = dev_get_drvdata(dev);
>  	struct msm_drm_private *priv = ddev->dev_private;
> -	struct msm_kms *kms = priv->kms;
> -
> -	/* TODO: Use atomic helper suspend/resume */
> -	if (kms && kms->funcs && kms->funcs->pm_suspend)
> -		return kms->funcs->pm_suspend(dev);
>  
> -	drm_kms_helper_poll_disable(ddev);
> +	if (!IS_ERR_OR_NULL(priv->pm_state))
> +		return 0;

Hmm, I don't think we want to completely abort suspending if it didn't succeed
previously. It would be easier if we just scrubbed the value if it's not valid.
So something like:

        if (WARN_ON(priv->pm_state))
                drm_atomic_state_put(priv->pm_state);

        priv->pm_state = drm_atomic_helper_suspend(ddev);
        if (IS_ERR(priv->pm_state)) {
                int ret = PTR_ERR(priv->pm_state);
                DRM_ERROR("Failed to suspend dpu, %d\n", ret);
                return ret;
        }

        return 0;

>  
>  	priv->pm_state = drm_atomic_helper_suspend(ddev);
> -	if (IS_ERR(priv->pm_state)) {
> -		drm_kms_helper_poll_enable(ddev);
> -		return PTR_ERR(priv->pm_state);
> -	}
>  
> -	return 0;
> +	return PTR_ERR_OR_ZERO(priv->pm_state);
>  }
>  
>  static int msm_pm_resume(struct device *dev)
>  {
>  	struct drm_device *ddev = dev_get_drvdata(dev);
>  	struct msm_drm_private *priv = ddev->dev_private;
> -	struct msm_kms *kms = priv->kms;
> +	int ret;
>  
> -	/* TODO: Use atomic helper suspend/resume */
> -	if (kms && kms->funcs && kms->funcs->pm_resume)
> -		return kms->funcs->pm_resume(dev);
> +	if (IS_ERR_OR_NULL(priv->pm_state))

If you take my suggestion above, this can become:

        if (WARN_ON(!priv->pm_state))
                return -ENOENT;

> +		return 0;
>  
> -	drm_atomic_helper_resume(ddev, priv->pm_state);
> -	drm_kms_helper_poll_enable(ddev);
> +	ret = drm_atomic_helper_resume(ddev, priv->pm_state);
> +	if (ret == 0)

nit: This is usually expressed as:

        if (!ret)

> +		priv->pm_state = NULL;
>  
> -	return 0;
> +	return ret;
>  }
>  #endif
>  
> diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h
> index fd88cebb6adb..2b81b43a4bab 100644
> --- a/drivers/gpu/drm/msm/msm_kms.h
> +++ b/drivers/gpu/drm/msm/msm_kms.h
> @@ -67,9 +67,6 @@ struct msm_kms_funcs {
>  	void (*set_encoder_mode)(struct msm_kms *kms,
>  				 struct drm_encoder *encoder,
>  				 bool cmd_mode);
> -	/* pm suspend/resume hooks */
> -	int (*pm_suspend)(struct device *dev);
> -	int (*pm_resume)(struct device *dev);
>  	/* cleanup: */
>  	void (*destroy)(struct msm_kms *kms);
>  #ifdef CONFIG_DEBUG_FS
> -- 
> 2.19.0.605.g01d371f741-goog
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS
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