Date: Thu, 30 Apr 2009 11:56:20 +0200 From: "Paul B. Mahol" <onemda@gmail.com> To: Gustau Perez <gperez@entel.upc.edu> Cc: freebsd-usb@freebsd.org Subject: Re: Signal sensitivity problem with if_rum Message-ID: <3a142e750904300256w4218f71bwfee97cdd1eb8252f@mail.gmail.com> In-Reply-To: <49F4B018.1000703@entel.upc.edu> References: <49F4B018.1000703@entel.upc.edu>
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On 4/26/09, Gustau Perez <gperez@entel.upc.edu> wrote: > > Hi, > > I think this is right place to post, if it is not, please let me know. It is not usb fault, it is driver side fault. > I'm experiencing problems with two different devices using if_rum. > One is a Hercules Guillemot and the other is a Linksys Cisco WUSB54GC > > The first one is about sensitivity, which is very low: for example, > I'm detecting just two or three networks around me (with windows them > detect around 14 or 15 networks) and the reported signal is very low. > Placing the sensor very near to my wireless network AP (which is a > FreeBSD machine with atheros card placing the txpower to 20) reports a > signal quality of 50% or 60%. > > Linux presents the same problem (my wife's laptop with ubuntu shows > the same figures, more or less). Instead with windows it works just fine. That contradicts with mine findings, linux rt73 driver works fine. > > The other one is that having such a low sensitivity makes those > dongles unusable when making large transfers, mostly when using scp/sftp > or sshfs (samba seems to make it work better for longer transfer, but > finally the problem appears). At some given point, the dongles seem to > lose contact with the AP (making ifconfig shows that wlan0 is still > associated), waiting for a period of time (usually one or two minutes) > the transfer continues. Probably both problems are related. > > In order to debug the problem I tried looking dmesg in both my AP and > my laptop (no trace). Tried looking at the ssh logs (when making large > transfers, no clue). In the only place I found something was in the > samba logs, only saying that there was a problem with the transfer > (broken pipe, the socket is closed). > > In the linux world, I found that the register which controls the > sensitivity is bbp17. Tried looking in > /usr/src/sys/dev/usb/wlan/if_rum.c, but I get lost. Tried with sysctl -a > | grep rum or grep wlan0, but no MiB related to sensitivity appeared. > > Is there anything I can try ? I use ndisgen(8) in such case(...), note that only CURRENT now have usb support for ndisulator. -- Paul
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