On Sat, 2018-09-08 at 00:22 +0200, Toke Høiland-Jørgensen wrote:

- I didn't get rid of the register_airtime() callback. As far as I can tell,
  only iwlwifi uses the tx_time field in the struct tx_info. Which means that
  we *could* probably use it for this and just make the other drivers set it;
  but I'm not sure what effects that would have in relation to WMM-AC for
  those drivers, so I chickened out. Will have to try it out, I guess; but it
  also depends on whether ath10k needs to be able to report airtime
  asynchronously anyway. So I'll hold off on that for a bit more.

I don't think you need to be concerned, the reporting through this has
no immediate effect as the driver would also have to set the feature
flag (NL80211_FEATURE_SUPPORTS_WMM_ADMISSION) for userspace to be able
to use WMM admission TSPECs, and getting tx_tspec->admitted_time to be
non-zero in ieee80211_sta_tx_wmm_ac_notify().

I just think that this may be desirable to drivers eventually, and/or
maybe iwlwifi wants to take advantage of the airtime scheduling
eventually, so having two APIs overlapping seems a bit strange.

johannes