Questions on ieee80211_frame_duration()

Hello Johannes,

in response to one of your brcm80211 review comments, I am trying to replace functions that calculate frame duration with Mac80211 counterparts.

As such, I have a hard time grasping this function:

http://lxr.free-electrons.com/source/net/mac80211/util.c#L108

A couple of questions:

a. The comment in the 'else' branch does not mention 802.11n, but I think it should. Agree ?

b. The long/short preamble choice applies to CCK rates only. But this function does not take that into account. Is that on purpose ?

c. In 802.11n there are 4 preamble types possible:
- long (CCK rates)
- short (CCK rates)
- green field
- mixed mode

The function does not seem to take the last two types into account. Should it ?

Bye, Roland.