• Leonard Crestez's avatar
    PM / devfreq: passive: Use non-devm notifiers · 0ef7c7cc
    Leonard Crestez authored
    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: 99613311 ("PM / devfreq: Add new passive governor")
    Signed-off-by: default avatarLeonard Crestez <leonard.crestez@nxp.com>
    Acked-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
    Signed-off-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
    0ef7c7cc
governor_passive.c 5.36 KB