Hi Heiner,
On 01/18/2016 09:52 PM, Heiner Kallweit wrote:
Yes, this seems to be the best solution. Driver should set this flag
before calling led_classdev_unregister. If the flag is set the -ENODEV
error will not be reported. It could be named LED_HW_ABSENT for
instance. Feel free to propose other ideas.
Setting such a flag from the driver might cause significant effort in different layers.
When we talk about thingm as an example, it uses the hid subsystem with the usbhid low level driver.
We would need a callback in the usbhid driver (to be notified when the device is unplugged)
and a way to propagate this event to the hid core.
Maybe simpler: We could ignore ENODEV errors if a function is called from led_classdev_unregister.
This way we wouldn't have to touch drivers. I think of something like this:
Ignoring -ENODEV errors for all devices would filter out also valid
error cases and hinder debugging.
How about adding a flag LED_HW_PLUGGABLE in addition to
LED_UNREGISTERING, and make the pluggable LED class drivers having set
it all the time. The -ENODEV error would be reported only
if !(LED_UNREGISTERING && LED_HW_PLUGGABLE).
--
Best Regards,
Jacek Anaszewski
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