Re: cfg80211 rfkill interface

[Johannes Berg <johannes@sipsolutions.net>]

Hi Arend,

> I am looking into implementing rfkill into our brcm80211 open-source
> driver. Our driver detects disable switch by an interrupt, but
> switching back does not give an interrupt. 

Interesting, but I guess it makes some sense.

> For the latter I wanted to use the rfkill_poll callback and
> wiphy_rfkill_start_polling.

Right, makes sense.

> However, I tried a wiphy_rfkill_stop_polling in the rfkill_poll
> callback when rf is unblocked, and this resulted in a system hang. 

Yeah, I'm not surprised. start_polling will work from anywhere, but
stop_polling needs to actually completely sync the poll stop so it can't
be done from within the poll or from within any rfkill callbacks.

> So I moved the wiphy_rfkill_stop_polling to the start callback. Does
> that make sense or is there another way you would recommend?

I think that makes sense.

However, where do you start polling? You have to poll even if the device
is not start()ed, I guess?

johannes