Fast Bits Lab

Turn off Madwifi Retry

admin — Fri, 04 Dec 2009 22:58:51 +0000

set ATH_TXMAXTRY to 1 in if_athvar.h

set sc->sc_mrretry=0 in if_ath.c

Madwifi locks (kernal freeze) up when creating adhoc mode

admin — Fri, 04 Dec 2009 21:36:46 +0000

Because the network service conflict with madwifi. Do the following:

1) Network service need to be turned off

System->preference->sessions
make sure the network manager applet is checked
There will be an icon on the right top corner for network management
Disable the network manager using the UI icon by right click the icon->disable netowrking
Verify the network manager is disable by left click the icon (you should see network disable)

2) reboot

3) Verify again the network manager is disable by left click the icon (you should see network disable)

4) Try to create the adhoc mode by using wlanconfig, it should not have kernal panic anymore =)

redirect printk message

admin — Thu, 21 May 2009 21:54:00 +0000

sudo cat /proc/kmsg

jiffies converts to time

admin — Wed, 06 May 2009 00:01:58 +0000

seconds = jiffies/HZ

per packet rate

admin — Tue, 05 May 2009 23:37:51 +0000

In the ath_rx_tastket funcion, the real rate KMbps can be obtained by the following value:

sc->sc_hwmap[ds->ds_rxstat.rs_rate].ieeerate/2;

Pass per packet Rssi and Rate to user space

admin — Tue, 05 May 2009 19:08:48 +0000

global value store the per packet Rssi and Rate value. Then use the ath_stats to store the value when ath_rx_tasklet is called. Use ioctl to retrieve the stats information.

In iperf Server.cpp (received side), do the following:
1) copy header file from madwifi to the current directory

wireless.h
ath_desc.h
if_athioctl.h

2) include all 3 files in (1) and the following in Server.cpp

3) add a function in Server.cpp to get the rssi and rate values using ioctl called, detail:


const char *infname = "wifi0";
struct ifreq ifr ;
struct ath_stats cur,total;

strncpy(ifr.ifr_name,ifname,sizeof(ifr.ifname));
ifr.ifr_data = (caddr_t) &total; 

ioctl(sock_id, SIOCGATHSTATS, &ifr)

return total.ast_rx_rssi;

4) output data in a file

Per packet rssi

admin — Tue, 05 May 2009 18:38:02 +0000

Read the value from ds->ds_rxstat.rs_rssi in ath_rx_tasklet in the code for “rx_accept:”. Read it right at the end of this case statement.

OFDM in Madwifi

admin — Tue, 05 May 2009 18:29:48 +0000

sc->sc_useintmit = 0; // is set to 1 by default so change it to 0

iperf server and client setup

admin — Sun, 03 May 2009 21:35:48 +0000

Server:
iperf -s -u -i5
Client:
iperf -c [ip address] -u -t [x second] -b [user rate in Mbps]