Re: 2.1.111: IDE DMA disabled...BLAH...BLAH...

Alan Cox (
Wed, 29 Jul 1998 11:31:59 +0100 (BST)

> adequately explained by something being out-of-spec, whether it's the
> cable or the chipset being bad.
> But that doesn't change the fact that people see corruption that goes away
> when they disable DMA.

Linus - Yes there is something wrong
No it cannot be DMA if DMA goes back to 1.3.20, almost every report
says it started in 2.1.x, most are not UDMA but older DMA

The only common theme right now seems to be SMP and SCSI, and thats SMP
machines in the SCSI case (not option), unknown in the IDE case.

The only known actual problem is BX chipsets and older versions of the Cyrix
detect where DMA corruption is one possible result but plain not working
is the normal case.

> The _only_ thing I ask for is that DMA be disabled by default, or at least
> disabled when there is any reasonable cause fr doubting the hardware.
> David Miller reports that certain windows drivers have a black-list, and
> that may be what we need to have. It certainly indicates that somebody
> else is aware of problems.

Dave then discovered he was wrong. Please read all DaveM's mail on the
subject. That was a PIO3/4 blacklist - which isnt DMA related.


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