The problem is solved . XP shows wrong info . You should uninstall your DVD-ROM drive in peripheral list then uninstall the IDE channel on which it is plugged . Reboot the computer . at reboot XP will reinstall the IDE channel and the DVD ROM drive . the DVD ROM drive will be in PIO mode .
Set "enable DMA mode" then reboot . At reboot drive should be detected/showed in DMA mode 2 by XP .
Cfitz that does not matter . To be honest "Optical Disc" , most people flash their drives in DMA mode but i have seen somewhere ( i don't remember
) advices saying to use PIO mode ( perhaps it is because it is more compatible ? ) . You don't have to blame yourself .
The KR7A uses a VIA KT266A chipset ( Northbridge ) . VIA Southbridges which controls IDE channels are the cause of the DMA 0 issue because it cannot recognise an DMA mode 3 tranfer mode for optical drives ( only Lite-On used it for the LTD-166S by mistake ) .
It is not a VIA's fault because no manufacturer had ever planned to manufacture optical drives using DMA mode 3 and VIA knew it .
Now we know there is a problem with VT8363/VT8363A Southbridges ( used with KT133/133A Northbridges ) and VT8366 Southbridge ( used with
KT266A Northbridge ) .
When you plug an optical drive to an ATA 33 cable , the cable LIMITS the drive transfer rate to DMA mode 2 because the cable cannot handle more , so in this case even with a VIA Southbrige there is no issues .
When you use an ATA 100 or higher cable ( 133 ) with a VIA Southbridge , the cable does not limits anymore transfer rate . So the drive tries to use DMA mode 3 but the VIA Southbridge fails in recognising DMA mode 3 and instead set it in DMA mode 0 ( which exists for logical reasons but is not used too ) for unknown reasons .
Lite-On has solved this issue easily by setting the maximum LTD-166S transfer rate at DMA mode 2 instead of DMA mode 3 in DSOF Firmware and later .