ad0: TIMEOUT - WRITE_DMA retrying (2 retries left) LBA=xxx

Scott Long scottl at
Thu Sep 30 18:55:27 PDT 2004

Tristan wrote:
> On Fri, 1 Oct 2004 03:28:38 +0200
> Marius Strobl <marius at> wrote:
>>On Thu, Sep 30, 2004 at 08:52:27PM -0400, Ken Smith wrote:
>>>On Fri, Oct 01, 2004 at 09:35:15AM +0930, Tristan wrote:
>>>>FreeBSD 6.0-CURRENT with GENERIC kernel built 27th Sep.
>>>>On a SunBlade 100 I see these messages regularly when
>>>>dma is enabled. The messages go away when I either use
>>>>atacontrol to set the mode to PIO4 or set hw.ata.ata_dma to 0
>>>>I do get data corruption on the disk if left in DMA mode.
>>>Just FYI my primary test machine is a SunBlade 100, it seems to
>>>be doing OK with a kernel built from this morning's source.  I've
>>>been doing most of my builds from an NFS server though, I'll do
>>>a check with a full buildworld which will use the local drive more.
>>>>ad0: 14594MB <ST315310A/3.28> [29651/16/63] at ata2-master UDMA66
>>>>acd0: CDRW <LTN486S/YSU1> at ata2-slave PIO4
>>>>ata3-master: DMA limited to UDMA33, non-ATA66 cable or device
>>>>ad1: 39266MB <IBM-DTLA-305040/TW4OA60A> [79780/16/63] at ata3-master UDMA33
>>>>Mounted root from ufs:/dev/ad0a.
>>>Is the data corruption spread across both drives, or just ad1?  That
>>>message about the cable or device being limited could be a clue.
>>Did you replace the cable of the primary channel? AFAIK on Blade 100
>>there's a hardware bug that causes data corruption when using UDMA66
>>and Sun ships them with a 40-pin cable as sort of a work-around. So
>>these non-ATA66 cable messages should be rather normal on Blade 100.
>>Not all revisions might be affected though.
> The primary channel is using the Sun Supplied cable, which appears
> to be an 80 wire cable. The message about "non-ATA66 cable or device"
> is expected because that cable is only a 40 wire cable. that seems to
> be a non-issue anyway, as it is only ad0 that is having errors.
> I've had a few people say to disconnect the CDROM and see what happens,
> perhaps its also worth trying the CDROM in UDMA mode, so I'm not mixing
> modes ?

Detaching the CDROM would be an easy first test.  The CDROM is likely
wanting to use WDMA mode which itself can be problematic (and is why
FreeBSD turns it off by default).


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