On Tue, Oct 17, 2017 at 06:16:23PM +0800, Jeffy Chen wrote: > When the pwm driver is unbound while the pwm is still requested, the > pwm core would not actually remove the pwmchip(return -EBUSY instead). > > So it would hold some references to the invalid resources(e.g. pwmchip). > > And the customer who requested the pwm would have those references too, > and may crash the kernel when trying to access them later. > > Add a dummy pwmchip, and assign orphan pwms to it to avoid that. > > Signed-off-by: Jeffy Chen <jeffy.c...@rock-chips.com> > --- > > Changes in v4: > Fix compile warning. > > Changes in v3: > Assign orphan pwms to dummy pwmchip instead of adding device link in the > customer driver.
What happened to this? Device links were specifically designed to avoid situations like these. A dummy PWM chip doesn't seem like the right solution to this. Thierry
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