URGENT README :: Rogier (Re: DMA Disabled.)

Andre Hedrick (andre@suse.com)
Fri, 27 Aug 1999 20:19:19 -0700 (PDT)

You got it right Rogier.
There is an uncorrectable timing chatter between the DMA mode 2 WD31600
and the UDMA Maxtor 92720U8. This is really problematic on the all PIIXx
chipsets that I have observed. It has nothing to do with Intel's
hardware, it is an issue between the two drive venders.

WD + Maxtor (same channel) == cat and dog in bag.
(One animal is going to damage the other.)

Disable all DMAing for data safety and split the devices to separate
channels. I do not care what is where. I fear that you will find
FS-Corruption from the hardware level. I spent four weeks and daily
reinstalls to finally pick up the phone and call Maxtor.
(Note that WD does not care about Linux, not a viable OS).

There is on a pretty way to impliment this kind of detection, or I would
have.

Andre Hedrick
The Linux IDE guy

On Fri, 27 Aug 1999, Rogier Wolff wrote:

>
> Hi,
>
> I have a new UDMA drive (Just because it's big) in a relatively old
> computer. It is the slave drive to an WD31600 drive. That WD drive is
> on a blacklist, although it DMA-ed just fine with me before it got on
> that blacklist.
>
> Anyway, once I start putting data onto my Maxtor 92720U8, it usualy
> reports "timeout waiting for DMA complete IRQ, disabeling DMA" after a
> while and continues in PIO mode.
>
> Can this be related to the WD drive? Should I swap them around
> (i.e. make the Maxtor the master)? Will that help? The second IDE bus
> is not available for one of these drives. So "why don't you put the
> Maxtor on the second IDE bus" is not an option.
>
> Machine: P120, 32Mb RAM.
> Kernel: 2.2.9 and 2.2.10
>
> I should one day make the machine boot off the new disk, and throw
> away the old disk, but I just can't find the time to do that... Of
> course, the new disk is filling up quickly, and where do you leave
> that 27G while repartitioning... :-)
>
> Roger.
>
> --
> ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
> *-- BitWizard writes Linux device drivers for any device you may have! --*
> ------ Microsoft SELLS you Windows, Linux GIVES you the whole house ------
>
>
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