Re: IDE problem: linux-2.5.17

[Vojtech Pavlik <vojtech@suse.cz>]

On Thu, May 23, 2002 at 04:27:39PM +0200, Martin Dalecki wrote:
> 
> > hda: dma_intr: status=0x51 { DriveReady SeekComplete Error }
> > hda: dma_intr: error=0x84 { DriveStatusError BadCRC }
> > hda: dma_intr: status=0x51 { DriveReady SeekComplete Error }
> > hda: dma_intr: error=0x84 { DriveStatusError BadCRC }
> > hda: dma_intr: status=0x51 { DriveReady SeekComplete Error }
> > hda: dma_intr: error=0x84 { DriveStatusError BadCRC }
> > hda: dma_intr: status=0x51 { DriveReady SeekComplete Error }
> > hda: dma_intr: error=0x84 { DriveStatusError BadCRC }
> 
> Since this error can be expected to be quite common.
> Its an installation error. I will just make the corresponding
> error message more intelliglible to the average user:
> 
> hda: checksum error on data transfer occurred!
> 
> Would have hinted you propably directly at what's wrong.

There is a routine in the IDE code to decrease transfer speed in case of
these problems. And it is there for a good reason - many (namely UDMA66)
mainboards have incorrectly wired IDE traces and can never achieve full
UDMA speeds, and there is no way to know.

For that I've also created UDMA_SLOW, which is even slower than UDMA_0
(16.6 MB/sec), which still has CRC protection, and needs even less
physical bandwidth than PIO4.

-- 
Vojtech Pavlik
SuSE Labs