Hi,
This is an experience report. I hope it is useful. I don't know if this is
known fact, but I've not been able to find it by searching the archives.
I've found only a reference to using MWDMA2 and loosing some
performance.
I've been using 2.4.6 (plain) on a couple of OSB4-based machines which boot
with UDMA2 enabled with no problem whatsoever. Recently, I've upgraded one of
them to 2.4.18-3smp (RedHat), which doesn't use DMA by default. Using hdparm
-d1 to activate DMA results either in an error message about OSB4 and freeze
or in a very severe corruption of the root partition (reinstallation
required).
After some experimentation, and by comparing /proc/ide/hda/settings with the
machine still running 2.4.6, I've tryied setting hdparm -X66 before using -d1
and it now works *reliably* and fast (21Mb/s).
If anybody wants further information about the hardware or wants to
experiment better fixes, please ask. I don't mind reinstalling the thing a few
more times. :-)
--
Jose Orlando Pereira
* mailto:[email protected] * http://gsd.di.uminho.pt/~jop *