[PATCH] ath6kl: Allow the radio to report 0 dbm txpower without timing out

[Valo, Kalle]

Eric Bentley <eric.bentley at lairdtech.com> writes:

> The ath6kl driver attempts to get the txpower value from the radio by first
> clearing the existing stored value and then watching the value to become
> non-zero.
>
> APs allow setting client power to values from -127..127, but this radio
> is not capable of setting values less then 0 and so will report txpower
> as 0dbm for both negative and 0 client power values.
>
> When the radio has txpower set to 0dbm txpower (equivalent to 1mw) the
> ath6kl_cfg80211_get_txpower() function will remain in the
> wait_event_interruptible_timeout() loop waiting for the value to be
> non-zero, and will eventually timeout. This results in a 5 second delay in
> response. However, the correct value of zero is eventually returned.
>
> The 6004 defaults to 63dbm which is then limited by regulatory and
> hardware limits with max of 18dbm (6003 max is 16dbm), therefore we can
> use values larger then these to be able to determine when the value has
> been updated.
>
> To correct the issue, set the value to a nonsensical value (255) and wait
> for it to change to the valid value.
>
> --
> Tested on both 6003 and 6004 based radios.  Return value of zero is
> correctly returned in an expected amount of time (similar to when
> returning non-zero values) when AP client power is set to both 0 and
> negative values.
>
> Signed-off-by: Eric Bentley <eric.bentley at lairdtech.com>

This is perfect now, thanks. I'll just remove the "--" line from the
commit log, that looks a bit weird.

-- 
Kalle Valo