linux-kernel - [PATCH] drm: mxsfb: fix runtime PM handling

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Date:   Fri, 13 Jul 2018 16:54:45 +0800
From:   Anson Huang <Anson.Huang@....com>
To:     marex@...x.de, airlied@...ux.ie, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Cc:     Linux-imx@....com
Subject: [PATCH] drm: mxsfb: fix runtime PM handling

As display power domain is combined with lcdif node
on some i.MX platforms like i.MX6SL, when lcdif driver
is enabled, the mxsfb_load is called to enable runtime
pm, and a pair of pm_runtime_get_sync and
pm_runtime_put_sync are also called, that will cause
generic power domain driver to disable lcdif power domain
and lcdif is no longer working, the lcdif power
should ONLY be turned off when display is disabled,
so move the pm_runtime_put_sync to mxsfb_unload
and remove the pm_runtime_get_sync in mxsfb_unload
as well, in this way, when display is enabled, the
lcdif power will be always ON until the display
is disabled.

Signed-off-by: Anson Huang <Anson.Huang@....com>
---
 drivers/gpu/drm/mxsfb/mxsfb_drv.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index ffe5137..1ba179b 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -235,7 +235,6 @@ static int mxsfb_load(struct drm_device *drm, unsigned long flags)

 	pm_runtime_get_sync(drm->dev);
 	ret = drm_irq_install(drm, platform_get_irq(pdev, 0));
-	pm_runtime_put_sync(drm->dev);

 	if (ret < 0) {
 		dev_err(drm->dev, "Failed to install IRQ handler\n");
@@ -264,6 +263,7 @@ static int mxsfb_load(struct drm_device *drm, unsigned long flags)
 err_irq:
 	drm_panel_detach(mxsfb->panel);
 err_vblank:
+	pm_runtime_put_sync(drm->dev);
 	pm_runtime_disable(drm->dev);

 	return ret;
@@ -279,7 +279,6 @@ static void mxsfb_unload(struct drm_device *drm)
 	drm_kms_helper_poll_fini(drm);
 	drm_mode_config_cleanup(drm);

-	pm_runtime_get_sync(drm->dev);
 	drm_irq_uninstall(drm);
 	pm_runtime_put_sync(drm->dev);

-- 
2.7.4