Re: [PATCH] ARM: OMAP2+: omap_device: Sync omap_device and pm_runtime after probe defer

[Tony Lindgren <tony@atomide.com>]

* Dave Gerlach <d-gerlach@ti.com> [170330 13:01]:
> 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.
> 
> Tested-by: Franklin S Cooper Jr. <fcooper@ti.com>
> Signed-off-by: Dave Gerlach <d-gerlach@ti.com>

Applying into omap-for-v4.11/fixes thanks. Will let this one sit
in Linux next for a while.

Regards,

Tony

> ---
>  arch/arm/mach-omap2/omap_device.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
> index e920dd83e443..f989145480c8 100644
> --- a/arch/arm/mach-omap2/omap_device.c
> +++ b/arch/arm/mach-omap2/omap_device.c
> @@ -222,6 +222,14 @@ static int _omap_device_notifier_call(struct notifier_block *nb,
>  				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);
> -- 
> 2.11.0
>