From 736f29cd6b7af9646a21a34866cd16277e03ee69 Mon Sep 17 00:00:00 2001
From: Tomi Valkeinen <tomi.valkeinen@ti.com>
Date: Wed, 4 Jul 2012 18:13:48 +0530
Subject: [PATCH 1/2] OMAPDSS: Use PM notifiers for system suspend

The current way how omapdss handles system suspend and resume is that
omapdss device (a platform device, which is not part of the device
hierarchy of the DSS HW devices, like DISPC and DSI, or panels.) uses
the suspend and resume callbacks from platform_driver to handle system
suspend. It does this by disabling all enabled panels on suspend, and
resuming the previously disabled panels on resume.

This presents a few problems.

One is that as omapdss device is not related to the panel devices or the
DSS HW devices, there's no ordering in the suspend process. This means
that suspend could be first ran for DSS HW devices and panels, and only
then for omapdss device. Currently this is not a problem, as DSS HW
devices and panels do not handle suspend.

Another, more pressing problem, is that when suspending or resuming, the
runtime PM functions return -EACCES as runtime PM is disabled during
system suspend. This causes the driver to print warnings, and operations
to fail as they think that they failed to bring up the HW.

This patch changes the omapdss suspend handling to use PM notifiers,
which are called before suspend and after resume. This way we have a
normally functioning system when we are suspending and resuming the
panels.

This patch, I believe, creates a problem that somebody could enable or
disable a panel between PM_SUSPEND_PREPARE and the system suspend, and
similarly the other way around in resume. I choose to ignore the problem
for now, as it sounds rather unlikely, and if it happens, it's not
fatal.

In the long run the system suspend handling of omapdss and panels should
be thought out properly. The current approach feels rather hacky.
Perhaps the panel drivers should handle system suspend, or the users of
omapdss (omapfb, omapdrm) should handle system suspend.

Note that after this patch we could probably revert
0eaf9f52e94f756147dbfe1faf1f77a02378dbf9 (OMAPDSS: use sync versions of
pm_runtime_put). But as I said, this patch may be temporary, so let's
leave the sync version still in place.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reported-by: Jassi Brar <jaswinder.singh@linaro.org>
Tested-by: Jassi Brar <jaswinder.singh@linaro.org>
Tested-by: Joe Woodward <jw@terrafix.co.uk>
Signed-off-by: Archit Taneja <archit@ti.com>
[fts: fixed 2 brace coding style issues]
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
---
 drivers/video/omap2/dss/core.c | 43 +++++++++++++++++++++-------------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/drivers/video/omap2/dss/core.c b/drivers/video/omap2/dss/core.c
index 5066eee10cc..58bd9c27369 100644
--- a/drivers/video/omap2/dss/core.c
+++ b/drivers/video/omap2/dss/core.c
@@ -32,6 +32,7 @@
 #include <linux/io.h>
 #include <linux/device.h>
 #include <linux/regulator/consumer.h>
+#include <linux/suspend.h>
 
 #include <video/omapdss.h>
 
@@ -201,6 +202,28 @@ int dss_debugfs_create_file(const char *name, void (*write)(struct seq_file *))
 #endif /* CONFIG_DEBUG_FS && CONFIG_OMAP2_DSS_DEBUG_SUPPORT */
 
 /* PLATFORM DEVICE */
+static int omap_dss_pm_notif(struct notifier_block *b, unsigned long v, void *d)
+{
+	DSSDBG("pm notif %lu\n", v);
+
+	switch (v) {
+	case PM_SUSPEND_PREPARE:
+		DSSDBG("suspending displays\n");
+		return dss_suspend_all_devices();
+
+	case PM_POST_SUSPEND:
+		DSSDBG("resuming displays\n");
+		return dss_resume_all_devices();
+
+	default:
+		return 0;
+	}
+}
+
+static struct notifier_block omap_dss_pm_notif_block = {
+	.notifier_call = omap_dss_pm_notif,
+};
+
 static int __init omap_dss_probe(struct platform_device *pdev)
 {
 	struct omap_dss_board_info *pdata = pdev->dev.platform_data;
@@ -224,6 +247,8 @@ static int __init omap_dss_probe(struct platform_device *pdev)
 	else if (pdata->default_device)
 		core.default_display_name = pdata->default_device->name;
 
+	register_pm_notifier(&omap_dss_pm_notif_block);
+
 	return 0;
 
 err_debugfs:
@@ -233,6 +258,8 @@ err_debugfs:
 
 static int omap_dss_remove(struct platform_device *pdev)
 {
+	unregister_pm_notifier(&omap_dss_pm_notif_block);
+
 	dss_uninitialize_debugfs();
 
 	dss_uninit_overlays(pdev);
@@ -247,25 +274,9 @@ static void omap_dss_shutdown(struct platform_device *pdev)
 	dss_disable_all_devices();
 }
 
-static int omap_dss_suspend(struct platform_device *pdev, pm_message_t state)
-{
-	DSSDBG("suspend %d\n", state.event);
-
-	return dss_suspend_all_devices();
-}
-
-static int omap_dss_resume(struct platform_device *pdev)
-{
-	DSSDBG("resume\n");
-
-	return dss_resume_all_devices();
-}
-
 static struct platform_driver omap_dss_driver = {
 	.remove         = omap_dss_remove,
 	.shutdown	= omap_dss_shutdown,
-	.suspend	= omap_dss_suspend,
-	.resume		= omap_dss_resume,
 	.driver         = {
 		.name   = "omapdss",
 		.owner  = THIS_MODULE,

From 373b43652150c9342168c846a1efbd81438ea241 Mon Sep 17 00:00:00 2001
From: Tomi Valkeinen <tomi.valkeinen@ti.com>
Date: Wed, 4 Jul 2012 18:13:49 +0530
Subject: [PATCH 2/2] OMAPDSS: fix warnings if CONFIG_PM_RUNTIME=n

If runtime PM is not enabled in the kernel config, pm_runtime_get_sync()
will always return 1 and pm_runtime_put_sync() will always return
-ENOSYS. pm_runtime_get_sync() returning 1 presents no problem to the
driver, but -ENOSYS from pm_runtime_put_sync() causes the driver to
print a warning.

One option would be to ignore errors returned by pm_runtime_put_sync()
totally, as they only say that the call was unable to put the hardware
into suspend mode.

However, I chose to ignore the returned -ENOSYS explicitly, and print a
warning for other errors, as I think we should get notified if the HW
failed to go to suspend properly.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Jassi Brar <jaswinder.singh@linaro.org>
Cc: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
---
 drivers/video/omap2/dss/dispc.c | 2 +-
 drivers/video/omap2/dss/dsi.c   | 2 +-
 drivers/video/omap2/dss/dss.c   | 2 +-
 drivers/video/omap2/dss/hdmi.c  | 2 +-
 drivers/video/omap2/dss/rfbi.c  | 2 +-
 drivers/video/omap2/dss/venc.c  | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 4749ac35646..397d4eee11b 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -384,7 +384,7 @@ void dispc_runtime_put(void)
 	DSSDBG("dispc_runtime_put\n");
 
 	r = pm_runtime_put_sync(&dispc.pdev->dev);
-	WARN_ON(r < 0);
+	WARN_ON(r < 0 && r != -ENOSYS);
 }
 
 static inline bool dispc_mgr_is_lcd(enum omap_channel channel)
diff --git a/drivers/video/omap2/dss/dsi.c b/drivers/video/omap2/dss/dsi.c
index ca8382d346e..14ce8cc079e 100644
--- a/drivers/video/omap2/dss/dsi.c
+++ b/drivers/video/omap2/dss/dsi.c
@@ -1075,7 +1075,7 @@ void dsi_runtime_put(struct platform_device *dsidev)
 	DSSDBG("dsi_runtime_put\n");
 
 	r = pm_runtime_put_sync(&dsi->pdev->dev);
-	WARN_ON(r < 0);
+	WARN_ON(r < 0 && r != -ENOSYS);
 }
 
 /* source clock for DSI PLL. this could also be PCLKFREE */
diff --git a/drivers/video/omap2/dss/dss.c b/drivers/video/omap2/dss/dss.c
index 770632359a1..d2b57197b29 100644
--- a/drivers/video/omap2/dss/dss.c
+++ b/drivers/video/omap2/dss/dss.c
@@ -731,7 +731,7 @@ static void dss_runtime_put(void)
 	DSSDBG("dss_runtime_put\n");
 
 	r = pm_runtime_put_sync(&dss.pdev->dev);
-	WARN_ON(r < 0 && r != -EBUSY);
+	WARN_ON(r < 0 && r != -ENOSYS && r != -EBUSY);
 }
 
 /* DEBUGFS */
diff --git a/drivers/video/omap2/dss/hdmi.c b/drivers/video/omap2/dss/hdmi.c
index 8195c7166d2..26a2430a702 100644
--- a/drivers/video/omap2/dss/hdmi.c
+++ b/drivers/video/omap2/dss/hdmi.c
@@ -138,7 +138,7 @@ static void hdmi_runtime_put(void)
 	DSSDBG("hdmi_runtime_put\n");
 
 	r = pm_runtime_put_sync(&hdmi.pdev->dev);
-	WARN_ON(r < 0);
+	WARN_ON(r < 0 && r != -ENOSYS);
 }
 
 static int __init hdmi_init_display(struct omap_dss_device *dssdev)
diff --git a/drivers/video/omap2/dss/rfbi.c b/drivers/video/omap2/dss/rfbi.c
index 3d8c206e90e..7985fa12b9b 100644
--- a/drivers/video/omap2/dss/rfbi.c
+++ b/drivers/video/omap2/dss/rfbi.c
@@ -141,7 +141,7 @@ static void rfbi_runtime_put(void)
 	DSSDBG("rfbi_runtime_put\n");
 
 	r = pm_runtime_put_sync(&rfbi.pdev->dev);
-	WARN_ON(r < 0);
+	WARN_ON(r < 0 && r != -ENOSYS);
 }
 
 void rfbi_bus_lock(void)
diff --git a/drivers/video/omap2/dss/venc.c b/drivers/video/omap2/dss/venc.c
index 2b8973931ff..3907c8b6ecb 100644
--- a/drivers/video/omap2/dss/venc.c
+++ b/drivers/video/omap2/dss/venc.c
@@ -402,7 +402,7 @@ static void venc_runtime_put(void)
 	DSSDBG("venc_runtime_put\n");
 
 	r = pm_runtime_put_sync(&venc.pdev->dev);
-	WARN_ON(r < 0);
+	WARN_ON(r < 0 && r != -ENOSYS);
 }
 
 static const struct venc_config *venc_timings_to_config(