Hi, Sorry about the long delay! > > I'm looking at power save mode provided by mwifiex driver and I see that > > current implementation is suboptimal and probably default settings quite > > suspicious for me. > > > > If I understand mwifiex driver correctly, it supports power save mode, > > but its setting is global for all interfaces. mwifiex is fullmac driver > > and power save mode is controlled by firmware and it is not possible to > > set it per-bssid. There is just command which affects all bssids. > > Ganapathi, please correct me if I'm wrong here. > > > > On the other hand, current cfg80211 layer supports controlling power > > save mode by NL80211_CMD_SET_POWER_SAVE and NL80211_CMD_GET_POWER_SAVE > > commands, which are per-net-interface, not per-wiphy-interface. > > > > Moreover NL80211_CMD_GET_POWER_SAVE does not use any driver callback, > > just use cached value from the last NL80211_CMD_SET_POWER_SAVE call. So > > kernel driver cannot provide correct state of power save by asking > > firmware for it. > > > > So currently it is not possible to implement power save mode for mwifiex > > driver correctly when more bssid interfaces for wiphy are used. > > > > Current situation is following: If I create two wlan interfaces (wlan0 > > and wlan1) for mwifiex wiphy and turn power save just only for wlan0 > > then mwifiex turn power save for both wlan0 and wlan1 (as firmware does > > not support per-bssid powe save), but cfg80211 for wlan1 still inform > > that power save is enabled. > > > > Do you have any idea how to fix this issue "properly"? So kernel would > > not lay about power save state of mwifiex interfaces? I guess that some > > extension or modification would be needed to core wireless cfg80211 > > code. I'm not sure I'd consider it "lying"? After all, powersave is sort of opportunistic anyway, and turned off when there's "enough" traffic, etc. But if you wanted to, I think you could just iterate all your interfaces and change wdev->ps for each one accordingly. It's a bit of a hack, but I'm not convinced that adding new API to nl80211 for this is worthwhile. That'd require disallowing the per-interface API, adding new API that is global, etc. So IMHO easier and good enough to just set wdev->ps for all of them whenever one of them is changed? > > And I have another question about power save. How should be handled > > WIPHY_FLAG_PS_ON_BY_DEFAULT flag? I see that kernel by default set it > > based on CONFIG_CFG80211_DEFAULT_PS compile option. But mwifiex driver > > always enable it independently of how is CONFIG_CFG80211_DEFAULT_PS was > > set at compile time. > > > > Should mwifiex driver respect CONFIG_CFG80211_DEFAULT_PS compile time > > option and do not enable WIPHY_FLAG_PS_ON_BY_DEFAULT when > > CONFIG_CFG80211_DEFAULT_PS is not set to power save? Uh, not sure really, sorry. I don't think it matters much? I think we should probably just remove the CFG80211_DEFAULT_PS config entirely. A lot of drivers won't really honour it, I suspect, and the runtime setting is trivially available. > > And the last question about power save mode and mwifiex. As power save > > mode for mwifiex firmware is global for all interfaces, what should be > > the correct behavior when there is wlan0 interface in managed/sta mode > > with enabled power save mode and then user add a new wlan1 interface in > > AP mode? Should driver turn off power save mode automatically (as it AP > > with enabled power save mode may cause problems) or should power save > > mode stay enabled (as user explicitly did not turned it off for wlan0)? That's up to the driver I guess, but I'd consider turning it off. Btw if you keep "wdev->ps" then you can undo this when the AP interface goes away, or in general when the list of interfaces changes. > > And what should be the correct behavior when there are two interfaces > > wlan0 and wlan1, both have power save mode turned off and user try to > > enable power save mode just for wlan0? Should mwifiex driver turn power > > save mode and therefore enable it for both wlan0 and wlan1? Or it should > > not enable power save mode until command is send for both wlan0 and > > wlan1 interfaces? Yeah, no idea :) I'd probably do something like this * keep wdev->ps as it is, so "lie" to userspace about it in some cases * disable powersave for AP interfaces completely (probably not even allowing it enabled); keep it for P2P_GO if supported though * whenever any interfaces come and go or any interface's state changes, recalculate the overall powersave state of the device and apply that johannes
