Tomas Winkler <tomasw@xxxxxxxxx> wrote: > On Mon, Dec 1, 2008 at 6:17 PM, Kalle Valo <kalle.valo@xxxxxxxxx> wrote: >> Johannes Berg <johannes@xxxxxxxxxxxxxxxx> writes: >> >>> On Mon, 2008-12-01 at 17:17 -0800, Vivek Natarajan wrote: >>>> This patch is based on Kalle's initial RFC patches on dynamic power save. >>>> Since ath9k/ath5k,stlc45xx and b43 need the driver to send the null >>>> frame, it is appropriate to do it from mac80211. >>>> This patch enables mac80211 to send a null frame and also to >>>> check for tim in the beacon if power save is enabled. >>> >>> One thing I forgot, do we need a special iwlwifi flag to turn this off? >>> Or can iwlwifi be programmed to let the host handle this (*), which >>> might be beneficial for interoperability and uniformity purposes? >> >> Having the null frame handling in firmware is faster and we might get >> some power savings from that. But is the saving observable, that's an >> another question :) > > This patch is not much relevant in actual saving , since this is the > waking up part, you are powering the whole nic up anyway. I agree but with PM bit on-off, this is what one can do to reduce some power consumption although not significant. If more significant savings is needed, we may need to implement PS-POLL or the APSD mechanism. But this is a good start to power save in mac80211. > The firmware handling of power save is more relevant in going to sleep > phase and sustaining where decision about sending the null frame is > faster then from host. The NIC is powered down in stages up to state > where only slow clock is ticking so this is rather time sensitive AFAIK, only iwlwifi has this firmware support and we need mac80211's support in this for ath9k/ath5k,stlc45xx and b43. I believe a powerful 2GHz host processor can manage these timings as a Windows driver for these vendor cards seems to support power save without firmware support. -- Vivek. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
