linux-kernel - Re: [PATCHv2 1/2] drm: atmel-hlcdc: Add PM suspend/resume support

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Message-id: <54E30E2B.5070407@samsung.com>
Date:	Tue, 17 Feb 2015 10:47:23 +0100
From:	Andrzej Hajda <a.hajda@...sung.com>
To:	Sylvain Rochet <sylvain.rochet@...secur.com>,
	Boris Brezillon <boris.brezillon@...e-electrons.com>,
	David Airlie <airlied@...ux.ie>,
	dri-devel@...ts.freedesktop.org,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Daniel Vetter <daniel@...ll.ch>,
	Kevin Hilman <khilman@...nel.org>,
	Wenyou Yang <wenyou.yang@...el.com>
Subject: Re: [PATCHv2 1/2] drm: atmel-hlcdc: Add PM suspend/resume support

Hi Sylvain,

Few comments below.

On 02/12/2015 09:49 PM, Sylvain Rochet wrote:
> On suspend: switch off CRTC if not already suspended with runtime PM
> 
> On resume: switch on CRTC if we were not already suspended from runtime
> PM while suspending.
> 
> Signed-off-by: Sylvain Rochet <sylvain.rochet@...secur.com>
> ---
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c | 60 ++++++++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
> 
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
> index 22c3cca..e22883b 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
> @@ -427,6 +427,36 @@ static void atmel_hlcdc_dc_lastclose(struct drm_device *dev)
>  	drm_fbdev_cma_restore_mode(dc->fbdev);
>  }
>  
> +static int atmel_hlcdc_dc_suspend(struct drm_device *dev, pm_message_t state)
> +{
> +	struct drm_crtc *crtc;
> +
> +	drm_modeset_lock_all(dev);
> +
> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> +		struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
> +		crtc_funcs->disable(crtc);
> +	}
> +
> +	drm_modeset_unlock_all(dev);
> +	return 0;
> +}
> +
> +static int atmel_hlcdc_dc_resume(struct drm_device *dev)
> +{
> +	struct drm_crtc *crtc;
> +
> +	drm_modeset_lock_all(dev);
> +
> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> +		struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
> +		crtc_funcs->enable(crtc);

What about crtc's which were disabled before suspend, they will be
enabled here unconditionally.


> +	}
> +
> +	drm_modeset_unlock_all(dev);
> +	return 0;
> +}
> +
>  static int atmel_hlcdc_dc_irq_postinstall(struct drm_device *dev)
>  {
>  	struct atmel_hlcdc_dc *dc = dev->dev_private;
> @@ -488,6 +518,8 @@ static struct drm_driver atmel_hlcdc_dc_driver = {
>  	.driver_features = DRIVER_HAVE_IRQ | DRIVER_GEM | DRIVER_MODESET,
>  	.preclose = atmel_hlcdc_dc_preclose,
>  	.lastclose = atmel_hlcdc_dc_lastclose,
> +	.suspend = atmel_hlcdc_dc_suspend,
> +	.resume = atmel_hlcdc_dc_resume,

These callbacks are obsolete and should not be used, additionally core
don't call them if drm_device have DRIVER_MODESET flag.

>  	.irq_handler = atmel_hlcdc_dc_irq_handler,
>  	.irq_preinstall = atmel_hlcdc_dc_irq_uninstall,
>  	.irq_postinstall = atmel_hlcdc_dc_irq_postinstall,
> @@ -559,6 +591,33 @@ static int atmel_hlcdc_dc_drm_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PM
> +static int atmel_hlcdc_dc_drm_suspend(struct device *dev)
> +{
> +	struct drm_device *drm_dev = dev_get_drvdata(dev);
> +	pm_message_t message;
> +
> +	if (pm_runtime_suspended(dev) || !drm_dev)

Nitpick, !drm_dev is always false, is not?

> +		return 0;
> +
> +	message.event = PM_EVENT_SUSPEND;
> +	return atmel_hlcdc_dc_suspend(drm_dev, message);

If you remove obsolete callbacks you can move suspend code here,
the same for resume.

> +}
> +
> +static int atmel_hlcdc_dc_drm_resume(struct device *dev)
> +{
> +	struct drm_device *drm_dev = dev_get_drvdata(dev);
> +
> +	if (pm_runtime_suspended(dev) || !drm_dev)
> +		return 0;
> +
> +	return atmel_hlcdc_dc_resume(drm_dev);

Ditto x2

Regards
Andrzej

> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(atmel_hlcdc_dc_drm_pm_ops,
> +		atmel_hlcdc_dc_drm_suspend, atmel_hlcdc_dc_drm_resume);
> +
>  static const struct of_device_id atmel_hlcdc_dc_of_match[] = {
>  	{ .compatible = "atmel,hlcdc-display-controller" },
>  	{ },
> @@ -569,6 +628,7 @@ static struct platform_driver atmel_hlcdc_dc_platform_driver = {
>  	.remove	= atmel_hlcdc_dc_drm_remove,
>  	.driver	= {
>  		.name	= "atmel-hlcdc-display-controller",
> +		.pm	= &atmel_hlcdc_dc_drm_pm_ops,
>  		.of_match_table = atmel_hlcdc_dc_of_match,
>  	},
>  };
> 

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