Re: 2.1.111: IDE DMA disabled?

Alan Cox (
Mon, 27 Jul 1998 02:39:28 +0100 (BST)

> Ouch. I'm tasked with supporting a few hundred Dells, all with WDC drives
> and all running Linux (2.0, so far). And all with UDMA not only enabled,
> but *forced* via hdparm because the users demand it and don't believe it's
> already turned on.
> Methinks I'm in trouble.

I dont have enough data giving brand names to answer that one yet. I've mailed
the folks who have sent me reports asking about drive brands.

WDC btw say that their drives are compliant but that motherboards with
overclocked PCI busses will sometimes fail to work in both DMA and PIO3/4
modes. The impression I get reading between the lines is that they are
tighter on spec requirements than some other vendors. Nevertheless they
say their UDMA is right.

Someone said they had an actual reference to DMA problems on the WDC site
can they provide the actual URL for this.


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