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

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Message-ID: <20150210150557.235fa139@bbrezillon>
Date:	Tue, 10 Feb 2015 15:05:57 +0100
From:	Boris Brezillon <boris.brezillon@...e-electrons.com>
To:	Sylvain Rochet <sylvain.rochet@...secur.com>
Cc:	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>
Subject: Re: [PATCH 1/2] drm: atmel-hlcdc: Add PM suspend/resume support

Hi Sylvain,

On Tue, 10 Feb 2015 14:40:45 +0100
Sylvain Rochet <sylvain.rochet@...secur.com> 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..4c89bd2 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);

Please replace that line by:

		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);

Ditto:
		crtc_funcs->enable(crtc);

> +	}
> +
> +	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,
>  	.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)
> +		return 0;
> +
> +	message.event = PM_EVENT_SUSPEND;
> +	return atmel_hlcdc_dc_suspend(drm_dev, message);
> +}
> +
> +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);
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(atmel_hlcdc_dc_drm_pm_ops,
> +		atmel_hlcdc_dc_drm_suspend, atmel_hlcdc_dc_drm_resume);
> +

Do we really need to register both SIMPLE_DEV_PM_OPS and drm_driver
suspend/resume functions.
I thought the suspend/resume callbacks were called by DRM core code
as part of the PM class specific operations.
However, exynos driver seems to do the same, so this might well be
required.

Best Regards,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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