On 02/08/2013 10:20 AM, Johannes Berg wrote:
On Wed, 2013-02-06 at 12:48 +0100, Marco Porsch wrote:
For mesh Awake Windows wakeup on SWBA (beacon_get_tim) and start
a timer which triggers a doze call on expiry.
That seems questionable -- drivers are not required to request each
beacon. I know you only want to make it work on ath9k, but I don't think
"stretching" the API, without even documenting it, is a good idea.
Currently, we already use ieee80211_beacon_get_tim as time reference for
mesh sync's adjust_tbtt. And, as far as I know, all mesh-capable drivers
use the call for each and every beacon.
So what would you recommend: keep using beacon_get and adding
documentation - or - creating an exported callback for awake_window_start?
+static inline void mps_queue_work(struct ieee80211_sub_if_data *sdata,
+ enum mesh_deferred_task_flags flag)
+{
+ set_bit(flag, &sdata->u.mesh.wrkq_flags);
+ ieee80211_queue_work(&sdata->local->hw, &sdata->work);
+}
Doing any sort of wakeup from here is also undesirable -- the workqueue
might actually sometimes be blocked for quite a while, I believe.
Yeah, right. Now that the hrtimer stuff is gone, I will check if the
remaining contexts allows skipping the work queue for wakeups.
+/**
+ * ieee80211_mps_hw_conf - check conditions for mesh PS and configure driver
+ *
+ * @sdata: local mesh subif
+ */
+void ieee80211_mps_hw_conf(struct ieee80211_sub_if_data *sdata)
+{
+ struct ieee80211_local *local = sdata->local;
+ bool enable;
+
+ enable = mps_hw_conf_check(local);
+
+ if (local->mps_enabled == enable)
+ return;
+
+ if (enable) {
+ mps_hw_conf_sta_prepare(local);
+ local->hw.conf.flags |= IEEE80211_CONF_PS;
+ } else {
+ local->hw.conf.flags &= ~IEEE80211_CONF_PS;
+ }
+
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
For some reason I thought this was supposed to be covered by the new
mesh PS callbacks, why do you still need hw conf?
Or wait -- this is only for general enable/disable, depending on the
other interfaces? I guess that's ok.
+ /* simple Deep Sleep implementation: only wake up for DTIM beacons */
+ if (sta->local_pm == NL80211_MESH_POWER_DEEP_SLEEP)
+ skip = tim->dtim_count ? tim->dtim_count : tim->dtim_period;
+ /*
+ * determine time to peer TBTT (TSF % beacon_interval = 0).
+ * This approach is robust to delayed beacons.
+ */
+ tsf_peer = tsf_local + sta->t_offset;
+ nexttbtt_interval = sta->beacon_interval * skip -
+ do_div(tsf_peer, sta->beacon_interval * skip);
+
+ mps_dbg(sta->sdata, "updating %pM next TBTT in %dus (%lldus awake)\n",
+ sta->sta.addr, nexttbtt_interval,
+ (long long) tsf_local - sta->nexttbtt_tsf);
+
+ sta->nexttbtt_tsf = tsf_local + nexttbtt_interval;
+ sta->nexttbtt_jiffies = jiffies + usecs_to_jiffies(nexttbtt_interval);
+
+ mod_timer(&sta->nexttbtt_timer, sta->nexttbtt_jiffies +
+ usecs_to_jiffies(BEACON_TIMEOUT));
Is that some sort of recovery? jiffies can be up to 20ms (I think, in
that order of magnitude anyway) inaccurate.
Yeah, that timer just hits as recovery in case a beacon is not received.
Then it projects the next TBTT and goes to sleep again.
Thanks,
--Marco
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