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SubjectRe: UMC UM8886BF IDE DMA not usable
On Sun, 7 Feb 1999, Martin Mares wrote:

> Hello,
>
> > > > The /proc/pci entry for the IDE chipset is the following:
> > > > Bus 0, device 18, function 1:
> > > > IDE interface: UMC UM8886BF (rev 16).
> > > > Fast devsel. Master Capable. No bursts.
> > > > Non-prefetchable 32 bit memory at 0x1f0 [0x1f0].
> > > > Non-prefetchable unknown memory at 0x3f0 [0x3f6].
> > > > Non-prefetchable 32 bit memory at 0x170 [0x170].
> > > > Non-prefetchable unknown memory at 0x370 [0x376].
> > >
> > > There is no address space for DMA-Busmaster.
> >
> > Therefore it is a problem in the Linux PCI support,
> > since this case should never happen nowadays.
> >
> > I have copied Martin (PCI guy) on this, so he can have a look.
>
> In this case, it's surely a hardware problem -- look at the /proc/pci
> entry above to see that the device is claiming these are _memory_
> regions, not I/O regions (!!), so I completely understand that the
> kernel didn't assign any I/O addresses to it. :-|
>
> Probably the only thing we can do is to add an exception to the
> PCI probing code to circumvent this bug. I'll look at it tomorrow.

I have a 486 UMC board sitting on top of my main system that I a can test
also and help with the work around. I would bet that this chipset has
never reported this in the past and only did this in the most recent
kernels. This is a result of listing it as an ide controller in
ide-pci.c.

Cheers,
Andre Hedrick
The (NEW) Linux IDE guy

http://www.dyer.vanderbilt.edu/server/udma/

You just need a bigger hammer, or learn how to swing the one you have better.
(C) me.....



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