Re: [reiserfs-dev] Re: IDE problem: linux-2.5.17

[Vojtech Pavlik <vojtech@suse.cz>]

On Thu, May 23, 2002 at 08:00:05PM +0400, Oleg Drokin wrote:
> Hello!
> 
> On Thu, May 23, 2002 at 04:44:26PM +0200, Martin Dalecki wrote:
> 
> > It's most likely the cable. The error comes directly from the
> > status register of the drive. The drive is reporting that it got
> > corrupted data from the wire. This will be only checked in the
> > 80 cable requiring DMA transfer modes. So if the drive resorts to
> > slower operation all will be fine. If it does not - well
> > you see the above...
> 
> Note, that errors are only appearing on hdb (barracuda drive),
> but errors go away once I disable DMA on hda (IBM drive).
> So the DMA is apparently is still on.
> Hm, or is there some trick that if only one drive on the channel
> operates in DMA mode and second on in PIO mode, then everything resorts to PIO
> of some sort? But hdparm seems not to confirm that.

It's probably because in DMA mode the IBM drive has different electrical
properties on the cable.

> 
> > It can of course be as well that the host chip driver is simply
> > programming the channel for too aggressive values.
> 
> BTW, that's
> VP_IDE: IDE controller on PCI bus 00 dev 39
> VP_IDE: chipset revision 6

Doesn't tell much ...

> Usually I see something like this:
> hdb: dma_intr: error=0x84 { DriveStatusError BadCRC }
> hdb: dma_intr: status=0x51 { DriveReady SeekComplete Error }
> ... (some such messages) ... followed by:
> hdb: dma_intr: error=0x84 { DriveStatusError BadCRC }
> hda: DMA disabled
> ide0: reset: success
> 
> Since this point, no more error messages.
> I checked and hdb is actually in DMA mode at this point.
> 
> Hm, I also noticed that hdb have this setting:
>  I/O support  =  3 (32-bit w/sync)

> Never saw this before. 

I think the driver sets this when it sees the problems ...

-- 
Vojtech Pavlik
SuSE Labs