ATA DMA FAILURE - non aligned DMA transfer attempted

Hi

I upgraded my home machine to -CURRENT recently and since then
(until now) I've not been able to play dvds on it.  This used to
work.

Hardware is:
atapci0: <VIA 82C686A UDMA66 controller> port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x37
6,0xffa0-0xffaf at device 7.1 on pci0
ata0: <ATA channel 0> on atapci0
ata0: [ITHREAD]
ata1: <ATA channel 1> on atapci0
ata1: [ITHREAD]
ad0: 76319MB <WDC WD800JB-00JJC0 05.01C05> at ata0-master UDMA66
acd0: DMA limited to UDMA33, device found non-ATA66 cable
acd0: DVDR <HP DVD Writer 635d/JPS3> at ata1-master UDMA33
acd0: FAILURE - INQUIRY ILLEGAL REQUEST asc=0x24 ascq=0x00 
acd0: FAILURE - INQUIRY ILLEGAL REQUEST asc=0x24 ascq=0x00 
cd0 at ata1 bus 0 target 0 lun 0
cd0: <HP DVD Writer 635d JPS3> Removable CD-ROM SCSI-0 device 
cd0: 33.000MB/s transfers
cd0: cd present [2278670 x 2048 byte records]

It's lying about the cable - it is a ATA66 cable, perhaps the port
on the motherboard is not UDMA-66 capable.

I get the following error:
acd0: FAILURE - REPORT_KEY ILLEGAL REQUEST asc=0x6f ascq=0x04 
acd0: FAILURE - REPORT_KEY ILLEGAL REQUEST asc=0x2c ascq=0x00 
ata1: FAILURE - non aligned DMA transfer attempted
acd0: setting up DMA failed

If I set the mode on acd0 to WDMA2, then it works fine.

Ian

--
Ian Freislich