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

Andrzej Hajda
2015-02-17T09:47:40Z

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@finsecur.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,
> },
> };
>