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Commit bfe945c8 authored by Shawn Guo's avatar Shawn Guo Committed by Greg Kroah-Hartman
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imx-drm: imx-drm-core: add basic suspend/resume support 



HDMI currently stops working after a system suspend/resume cycle.  The
cause is that the mode setting states in hardware gets lost and isn't
restored across the suspend/resume cycle.

The patch adds a very basic suspend/resume support to imx-drm driver,
and calls drm_helper_resume_force_mode() in .resume hook to restore the
mode setting states, so that HDMI can continue working after a system
suspend/resume cycle.

Since the suspend/resume hook can be called with drm_device pointer
being NULL from driver data, we need a check on the pointer in the
hooks.  And to avoid using a stale pointer from driver data, it also
clears driver data in .unload hook.

Signed-off-by: default avatarShawn Guo <shawn.guo@freescale.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b46355f0

drivers/staging/imx-drm/imx-drm-core.c

+33 −0
Original line number Diff line number Diff line
@@ -87,6 +87,8 @@ static int imx_drm_driver_unload(struct drm_device *drm) 
	drm_vblank_cleanup(drm);

	drm_mode_config_cleanup(drm);



	platform_set_drvdata(drm->platformdev, NULL);



	return 0;

}
@@ -648,6 +650,36 @@ static int imx_drm_platform_remove(struct platform_device *pdev) 
	return 0;

}



#ifdef CONFIG_PM_SLEEP

static int imx_drm_suspend(struct device *dev)

{

	struct drm_device *drm_dev = dev_get_drvdata(dev);



	/* The drm_dev is NULL before .load hook is called */

	if (drm_dev == NULL)

		return 0;



	drm_kms_helper_poll_disable(drm_dev);



	return 0;

}



static int imx_drm_resume(struct device *dev)

{

	struct drm_device *drm_dev = dev_get_drvdata(dev);



	if (drm_dev == NULL)

		return 0;



	drm_helper_resume_force_mode(drm_dev);

	drm_kms_helper_poll_enable(drm_dev);



	return 0;

}

#endif



static SIMPLE_DEV_PM_OPS(imx_drm_pm_ops, imx_drm_suspend, imx_drm_resume);



static const struct of_device_id imx_drm_dt_ids[] = {

	{ .compatible = "fsl,imx-display-subsystem", },

	{ /* sentinel */ },
@@ -660,6 +692,7 @@ static struct platform_driver imx_drm_pdrv = { 
	.driver		= {

		.owner	= THIS_MODULE,

		.name	= "imx-drm",

		.pm	= &imx_drm_pm_ops,

		.of_match_table = imx_drm_dt_ids,

	},

};