write operations appear to lose scsi interrupts and causes timeouts.
changes in this checkin include:
a nextdma bugfix causing a diagnostic check to erroneously trigger
Changed tail strategy to only use tail buffer for the minimal end slop
changed expected write dma overrun to 32 bytes.
turned on nextdma diagnostic check for dma end address since it
no longer gets triggerred by ethernet dma and helps debug scsi dma.
Added esp debugging printout and support.
a filesystem, but is not stable enough yet for general use.
increased priority of ethernet interrupts, mostly useful to aid debugging
of scsi interrupts while using an nfs disk.
added additional debugging output in the next dma driver.
perform extranneous cache flushes/purges before dma reads/ after dma writes
to aid debugging of scsi dma.
This fix removes putting 0xfeedbeef in the unused restart registers.
When that was done, the machine would panic after a short while
with 0xfeedbeef in the normal dma buffer registers. A restart
cycle is probably hapenning without an interrupt or something.
of DD_NEXT for regular dma transfers, and not just ethernet transmit.
Keep track of dma read/write direction and set it each time we start or
restart dma. This allows scsi to work, and doesn't appear to hinder ethernet.
dbj