XI-626 (Prism 2.5) lockup

Martin Stachon martin.stachon at tiscali.cz
Tue May 6 13:13:23 EDT 2003


Hello,
Prism & HostAP lockups during card reset are so unfamous, forcing people to use hardware
AP. During our testing, we reported one particular lockup case. We hope this could help to
solve the HostAP unstability problems.

During our testing the card was running fine, even with very low link quality. The
situation was following : we had a router running HostAP, linux client connected to it,
downloading 100MB file via FTP. Also SSH connection was active to the router. Using SSH,
channel was changed from 11 to 1 on HostAP. Suprisingly, the SSH connection did not close
(AP notified the client somehow?) The card was resetted because of the channel change. And
that locked up linux AP hard. On the screen was message about card reset. This seems to be
the reason of the failure : if a packet is recieved during card reset, card dies. The
solution might look like this : Mask interrupts before card reset (in case it is not
masked) (-just guessing in this) It could also help to deactive card RX (recieve) before
resetting the card.

Details : AP - CPU VIA C3 800 Mhz, MB MSI 6368PLE (PCI 2.2), 256 MB DIMM Kingston 133MHz.
Debian Linux 3 (Woody), kernel 2.4.20 WE 14, HostAP from CVS 13. 4. 2003 (no patches), one
ZCOM XI-626 in the machine, not sharing IRQ. Free IRQs avaiable (COMs, LPT, USB and other
unused hardware turned off in BIOS as well as in kernel) Signal level was good, CPU load
max 30%.

Kind regards,
    Slim &
    Martin Stachon

(CZFree.Net.Ostrava)




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