On Wednesday 08 August 2007 22:49:17 you wrote: > Richard Jonsson wrote: > > On Monday 06 August 2007 03:21:11 you wrote: > >> Richard Jonsson wrote: > >>> Isn't Desired TX power supposed to adapt so that higher bitrates are > >>> possible, with Bit Rate going lower if that is not enough to keep a > >>> good connection? > >> > >> Richard, > >> > >> Please grab a new copy of the port_to_mac80211 patch, and try the patch > >> below. It boosts the desired power by up to 5 dBm as signal - noise > >> decreases from 20 to 0. > >> > >> Larry > > > > Hard to say if there is a difference. I've noticed that signal quality > > changes between reboots. When I first tried this patch I couldn't get > > above 36M even at the AP, so I loaded the version without the patch. Same > > thing. So I rebooted and then all rates worked, even 11M. Even for the > > driver version that didn't work a few days ago. > > That is scary! That may mean that something is not being reset. The real > question is whether warm reboots are intrinsically different than cold > (power-off) reboots.
I've power cycled between reboots, unsure if I would get the same results on a soft reset. > > > New/updated observations: > > Rate scaling seems to work, but if it gets down to 1M it will not rise > > again unless I force it to a higher bitrate and run iperf for a few > > seconds before setting it to auto. This is even when signal is -5dBm and > > noise is -80dBm. I get a feeling it's a bit to sensitive as it will drop > > quickly at a few meters away. At this distance forced 54M still works > > well. > > Maybe this is due to small dips (0.5sec) in traffic flow?! > > I'm surprised that you get signal values as high as -5 dBm. My maximum is > about -35. I'm usually in the -40 range, even at 2 m from the AP. > That -5dBm signal is best case when AP's antenna is a few cm from the computers lid. In this position it often reads between -15 - -20dBm. If I move just a cm further away it drops to -30dBm which gradually decreases with distance. > > With the patch applied power is reported as 27dB in debugfs. With > > debug_xmitpower dmesg reports desired power to be 16.5 and actual 16.25. > > This is max when I manually set power through debugfs. After a while it's > > down to 10dB, even though only 1M works where I sit. > > > > Range seems to be higher for B-rates. Maybe this is just how things are, > > I lack experience. > > The CCCK (B) encoding is much different than OFDM (G) transmissions. I > would not be surprised to learn that its range were longer. > > The power setting that comes from mac80211 is 27 dBm, which is completely > bogus for what is supposed to be the FCC table. The regulatory limit is 20 > dBm EIRP (a fancy acronym that means take the antenna into account). I've > sent a fix for comment, but as is the usual case for mac80211, it will take > several days or weeks to get a response. The maximum power that a bcm43xx > device can use is encoded in the sprom. For most of them that quantity is > 18.5 dBm, corresponding to the regulatory limit of 20 minus a safety factor > of 1.5. I think that is there to prevent setting the power too high and > flunking the certification tests. The output that goes to the radio is thus > 18.5 less the gain of the antenna, which is also in the sprom with a usual > value of 2 dBm. That is why you see the code setting a Desired power of > 16.5 dBm. I see! I expected it to go to 18dBm. > > Initially, I thought that the performance of my BCM4311 fell off as the > power increased; however, that no longer happens. As a result, we can push > full power at all times and there seems to be no need to use the kind of > algorithm that you were testing. Don't tell the FCC, but we could relax IMHO there should eventually be some power scaling, as I understand wlan takes a fair amount of power. Ideally there should be different modes (powersave, performance) preferrably as an API common to all networking, at least wireless. Getting offtopic, just a thought. > that upper power limit as we will never try to get the device certified, > but then we would use extra power, and run the risk of burning out the > radio. If you decide to do that, please tell me the power setting at which > it fried! Heh, I might have tried if it was a usb stick ;) Since it's usable and since I got 54M/36M rate under no/high load in winxp under the same circumstances I believe power output is sufficient. > > With the patches that were pushed into wireless-dev a few minutes ago, I > suggest that you try bcm43xx-mac80211. It is getting at least as good, if > not better, performance than the BCM4301 or the softmac port to mac80211 > drivers do. We would also appreciate as much testing as possible as it will > help getting it merged into mainstream. That driver will require V4 > firmware. > > Thanks for your report, > > Larry Sure, I'll do that. Where do I get a current source? By git? (I forgot to add the mailinglist in the original mail, sorry) _______________________________________________ Bcm43xx-dev mailing list Bcm43xx-dev@lists.berlios.de https://lists.berlios.de/mailman/listinfo/bcm43xx-dev
