In <200008120558.e7C5wpM14531@flash.vaultron.com>
gillham@vaultron.com wrote:

> You appear to be correct, the patch doesn't seem to help my machine.
> The 'sip0' is probe ok, but when I specify it as the root device (or boot
> sysinst and use ifconfig) it reports the following:
> sip0: master abort 
> ... (repeatedly)
> sip0: transmit FIFO underrun; increasing Tx .... (flashes by too fast)
> 
> Apparently something is working though, as 'netstat -in' reports input
> and output packets.  Also, tcpdump -i sip0 (when booted via NFS on aue0)
> sees some broadcasts on the network.  I was able to use dhclient to get
> a lease after several timeouts, etc.  Unfortunately sip0 doesn't appear
> to be receiving very many packets, and perhaps not transmitting them as
> arp requests don't complete on the NIC or on the server.

I've committed some fixes to make sip work on my macppc,
but my problem is around receive filter configuration.
In your case, your sip can send/receive some packets
so it looks some PCI bus related problem.

According to the SiS 900 manual (which is available at
http://www.sis.com.tw/support/databook.htm),
there are some configurable PCI/DMA settings.
As noted if_sip.c, sc_tx_drain_thresh
and TX_MXDMA_??? values could be tuned.
(FreeBSD's if_sis.c uses 46 (1472byte) for drain thresh
 and 64byte for max DMA burst size.)
There is also REQALG bit in Configuration Register
which makes sip use "more conservative scheme" on
PCI bus requests. (I have not tested these, though.)
---
Izumi Tsutsui
tsutsui@ceres.dti.ne.jp