Re: ASUS KT266A/VT8233 board and UDMA setting

[Dmitri Pogosyan <pogosyan@phys.ualberta.ca>]

Alan Cox wrote:

> > Some RH kernels (may include yours) deliberately disable UDMA3, 4 and 5
> > on any VIA IDE controller. I don't know why. Unpatch your kernel and
> > it'll likely work.
>
> RH 2.4.2-x. That was before we had the official VIA solution to the chipset
> bug. It was better to be safe than sorry for an end user distro.
>

Yes, indeed.  Seems RH-2.4.16-0.13 kernel still enforces disabling UDMA>2 for
VIA,
by means of setting cable type to 40w, even if 80w is present

#cat /proc/ide/via

------------   ---Primary IDE-----Secondary IDE------
Read DMA FIFO flush:          yes                 yes
End Sector FIFO flush:         no                  no
Prefetch Buffer:                    yes                  no
Post Write Buffer:               yes                  no
Enabled:                               yes                 yes
Simplex only:                         no                  no
Cable Type:                        40w                 40w


If I force higher UDMA by ide0=ata66 kernel option, as  discussed in RH bug
35274,
ide0 zero is set to UDMA5    (not the cable though) and everything is working.

I'll file a bug against RH kernel.

                Thanks everybody, Dmitri