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PM / devfreq: passive: Use non-devm notifiers 

The devfreq passive governor registers and unregisters devfreq
transition notifiers on DEVFREQ_GOV_START/GOV_STOP using devm wrappers.

If devfreq itself is registered with devm then a warning is triggered on
rmmod from devm_devfreq_unregister_notifier. Call stack looks like this:

	devm_devfreq_unregister_notifier+0x30/0x40
	devfreq_passive_event_handler+0x4c/0x88
	devfreq_remove_device.part.8+0x6c/0x9c
	devm_devfreq_dev_release+0x18/0x20
	release_nodes+0x1b0/0x220
	devres_release_all+0x78/0x84
	device_release_driver_internal+0x100/0x1c0
	driver_detach+0x4c/0x90
	bus_remove_driver+0x7c/0xd0
	driver_unregister+0x2c/0x58
	platform_driver_unregister+0x10/0x18
	imx_devfreq_platdrv_exit+0x14/0xd40 [imx_devfreq]

This happens because devres_release_all will first remove all the nodes
into a separate todo list so the nested devres_release from
devm_devfreq_unregister_notifier won't find anything.

Fix the warning by calling the non-devm APIS for frequency notification.
Using devm wrappers is not actually useful for a governor anyway: it
relies on the devfreq core to correctly match the GOV_START/GOV_STOP
notifications.

Fixes: 996133119f ("PM / devfreq: Add new passive governor")
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
This commit is contained in:
Leonard Crestez 2019-08-08 19:54:08 +03:00 committed by MyungJoo Ham
parent 4294a779bd
commit 0ef7c7cce4
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/devfreq/governor_passive.c
View File

@ -165,12 +165,12 @@ static int devfreq_passive_event_handler(struct devfreq *devfreq,
p_data->this = devfreq;
nb->notifier_call = devfreq_passive_notifier_call;
ret = devm_devfreq_register_notifier(dev, parent, nb,
ret = devfreq_register_notifier(parent, nb,
DEVFREQ_TRANSITION_NOTIFIER);
break;
case DEVFREQ_GOV_STOP:
devm_devfreq_unregister_notifier(dev, parent, nb,
DEVFREQ_TRANSITION_NOTIFIER);
WARN_ON(devfreq_unregister_notifier(parent, nb,
DEVFREQ_TRANSITION_NOTIFIER));
break;
default:
break;