Linux-Hams archive - May 1998: Re: scc module buffers only up to 8 packets, with quick hack..

Re: scc module buffers only up to 8 packets, with quick hack..

Joerg Reuter (zbw@genext.net)
Tue, 05 May 1998 16:58:10 +0300


> Just to reassure you, I had a similar problem involving FBB forwarding.
>
> I tried altering the number of buffers with z8530drv.conf (this feature is
> mostly undocumented) unsuccessfully, so cheated and altered the default
> setting in the code.

That's not a cheat... It is a #define for a good reason. ;-)

> That, together with extending the maxkey time which
> was occassionally being exceeded, fixed my problems. The number of TX
> errors on sccstat dropped greatly, and my forwarding problems vanished.

That's interesting. I have no idea how TX underruns (an error condition
signaled by the Z8530 itself) could have anything to do with (de)queueing
of buffers. It may, however, trigger another problem. The kernel AX.25
does not recover from the retransmission state (i.e. when one or more
frames were lost) under a special condition. Jean-Paul has a fix for
this problem, I believe. (Check your transmitter for heat problems if
you can reproduce this behaviour, it only occurs when the other DXE
constantly cannot decode the last frame(s) of your transmission window).

vy 73,
Joerg Reuter ampr-net: ynyctk.nfynfwx@arctecho.com
Internet: pbr.zxfrwu@cybiko.com
www : http://poboxes.com/jreuter/

If God had intended man to smoke He would have set him on fire.