> This method doesn't have a hysteresis parameter because there's no > benefit to the cfg80211 code from having the hysteresis be handled by > hardware/driver in terms of the number of wakeups. At the same time > it would likely be less consistent between drivers if offloaded or > done in the drivers.
I'm not really sure I buy this. What if I configure a few ranges, and let's say one of the boundaries is -50dBm. Now if I sit just on that value of -50dBm and thus my signal fluctuates say -48..-52, I'd have to continuously wake up the host. You try to avoid that here, I think: + if (low > (s32) (last - hyst)) + low = last - hyst; + if (high < (s32) (last + hyst)) + high = last + hyst; but it's not clear to me that this is effective? Let's see. last is -52, so low will be -60 and high will be -50. Let's say hyst is 3 since I chose the ranges so closely. I'm guessing a higher hysteresis and larger ranges would actually be better, but let's stick to this for the sake of the example. last-hyst = -55, so low isn't > that, low = -60 last+hyst = -49, so high = -49 but now it still fluctuates around -50, so if I next hit -48 you do the same dance again with -50/-40, getting -51/-40 and never really applying a full hysteresis, no? I'll probably see an intermediate value of -50 at some point, but I'll never actually *report* it, so "last" can switch between -48 and -52 constantly in this scenario, no? I think it would make sense to unconditionally apply the hysteresis to low/high, i.e. always set low = low - hyst high = high + hyst so that you get "sticky" ranges once you're in them? > + if (!wiphy_ext_feature_isset(&rdev->wiphy, > + > NL80211_EXT_FEATURE_CQM_RSSI_LIST)) > + return > -EOPNOTSUPP; That check should be earlier in the function cfg80211_cqm_rssi_update(), no? johannes
