Patch "ARM: OMAP2+: omap_device: Sync omap_device and pm_runtime after probe defer" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

ARM: OMAP2+: omap_device: Sync omap_device and pm_runtime after probe defer

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm-omap2-omap_device-sync-omap_device-and-pm_runtime-after-probe-defer.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dave Gerlach <[email protected]>
Date: Thu, 30 Mar 2017 14:58:18 -0500
Subject: ARM: OMAP2+: omap_device: Sync omap_device and pm_runtime after probe defer

From: Dave Gerlach <[email protected]>

commit 04abaf07f6d5cdf22b7a478a86e706dfeeeef960 upstream.

Starting from commit 5de85b9d57ab ("PM / runtime: Re-init runtime PM states at probe error and driver unbind") pm_runtime core now changes device runtime_status back to after RPM_SUSPENDED after a probe defer. Certain OMAP devices make use of "ti,no-idle-on-init" flag which causes omap_device_enable to be called during the BUS_NOTIFY_ADD_DEVICE event during probe, along with pm_runtime_set_active.

This call to pm_runtime_set_active typically will prevent a call to pm_runtime_get in a driver probe function from re-enabling the omap_device. However, in the case of a probe defer that happens before the driver probe function is able to run, such as a missing pinctrl states defer, pm_runtime_reinit will set the device as RPM_SUSPENDED and then once driver probe is actually able to run, pm_runtime_get will see the device as suspended and call through to the omap_device layer, attempting to enable the already enabled omap_device and causing errors like this:

omap-gpmc 50000000.gpmc: omap_device: omap_device_enable() called from invalid state 1
omap-gpmc 50000000.gpmc: use pm_runtime_put_sync_suspend() in driver?

We can avoid this error by making sure the pm_runtime status of a device matches the omap_device state before a probe attempt. By extending the omap_device bus notifier to act on the BUS_NOTIFY_BIND_DRIVER event we can check if a device is enabled in omap_device but with a pm_runtime status of RPM_SUSPENDED and once again mark the device as RPM_ACTIVE to avoid a second incorrect call to omap_device_enable.

error and driver unbind")

---
 arch/arm/mach-omap2/omap_device.c |    8 ++++++++
 1 file changed, 8 insertions(+)

@@ -222,6 +222,14 @@ static int _omap_device_notifier_call(st
 				dev_err(dev, "failed to idle\n");
 		}
 		break;
+	case BUS_NOTIFY_BIND_DRIVER:
+		od = to_omap_device(pdev);
+		if (od && (od->_state == OMAP_DEVICE_STATE_ENABLED) &&
+		    pm_runtime_status_suspended(dev)) {
+			od->_driver_status = BUS_NOTIFY_BIND_DRIVER;
+			pm_runtime_set_active(dev);
+		}
+		break;
 	case BUS_NOTIFY_ADD_DEVICE:
 		if (pdev->dev.of_node)
 			omap_device_build_from_dt(pdev);

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/arm-omap2-omap_device-sync-omap_device-and-pm_runtime-after-probe-defer.patch