2.4.21 & 2.5.74 -- SATA/UDMA not set at boot

[John T Copeland]

Both kernels 2.4.21 and 2.5.74 leave the SATA drive in PIO mode after 
boot.  My system is Abit NF7-S with 2 IBM 100MHz parallel drives on 
IDE0, and 1 Western Digital 150 serial on IDE2.

NOTE: My boot drive in this case is the serial drive, and the parallel 
drives are auxiliaries.

The 2 parallel drives come up dma on, udma5 marked(hdparm /dev/hde and 
hdparm -i /dev/hde).  The serial drive of course is dma off, nothing 
marked.  There is no way to turn on DMA in the BIOS.

2.5.74 allows me to execute "hdparm -d1 -Xudma6 /dev/hde" while booting 
from a bootmisc.sh script.  If I try the same thing with 2.4.21 I get 
all kinds of errors, timeouts, other stuff and the EXT3 journal finally 
aborts and shutdown gives I/O errors.  I found out by trial and error 
that if I execute with 2.4.21:
1)hdparm -Xudma6 /dev/hde      This AOK, udma6 is on(marked)
2)hdparm -d1 /dev/hde               Some errors show up, dma is set, but 
udma6 is turned off(no mark)
3)hdparm -Xudma6 /dev/hde       udma6 back on(marked)
A hdparm -t /dev/hde verifies udma6 on and working.

Another point.  When my boot drive is /dev/hda, a parallel drive and the 
serial drive, /dev/hde is the auxiliary 2.4.21 allows me to "hdparm -d1 
-Xudma6 /dev/hde" while booting from a bootmisc.sh script.