On Tue, Feb 19, 2002 at 09:35:37AM +0100, Noud de Brouwer wrote:
> i have a ide question..
> i see my diskinterfaces being downgraded from time to time.
> 
> Feb 19 09:09:47 127 /netbsd: wd1: transfer error, downgrading to Ultra-DMA mode
> 2
> Feb 19 09:09:47 127 /netbsd: wd1(pciide1:0:0): using PIO mode 4, Ultra-DMA mode 
> 2 (Ultra/33) (using DMA data transfers)
> Feb 19 09:09:47 127 /netbsd: wd2(pciide1:0:1): using PIO mode 4, Ultra-DMA mode 
> 2 (Ultra/33) (using DMA data transfers)
> Feb 19 09:09:47 127 /netbsd: wd1a: aborted command, interface CRC error writing 

"interface CRC error" means that the data got corrupted while transfered on
the IDE bus. This mean thge signal/noise ratio of the bus isn't good enouth,
and the driver used a lower speed to work around this.
The cause of this is usually bad cables, or incompatible devices on the bus.

--
Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
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