hi,
I've got a problem with DVDRW drive on viaide controller. when I try read
something from it, the viaide driver downgrades mode from UDMA33 to PIO4
for cd (and everything works very slowly when using this drive). HDD
connected to the same cable works OK.
As suggested in NetBSD's list archive, I've tried different IDE cable with
only DVD drive connected, changed FSB in BIOS to the lowest value - 101MHz -
with the same result :(
2.0, 2.0.1 and 2.99.14 kernel with the same results :(

How can I solve this problem?


dmesg parts:

viaide0 at pci0 dev 7 function 1
viaide0: VIA Technologies VT82C596A (Apollo Pro) ATA33 controller
viaide0: bus-master DMA support present
viaide0: primary channel configured to compatibility mode
viaide0: primary channel interrupting at irq 14
atabus0 at viaide0 channel 0
viaide0: secondary channel configured to compatibility mode
viaide0: secondary channel interrupting at irq 15
atabus1 at viaide0 channel 1
[...]
atapibus0 at atabus1: 2 targets
cd0 at atapibus0 drive 1: <TOSHIBA ODD-DVD SD-R5272, 44RR503029, 1030> cdrom removable
cd0: 32-bit data port
cd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 2 (Ultra/33)


viaide0:1:1: lost interrupt
        type: atapi tc_bcount: 32 tc_skip: 0
cd0: transfer error, downgrading to Ultra-DMA mode 1
wd1(viaide0:1:0): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA data transfers)
cd0(viaide0:1:1): using PIO mode 4, Ultra-DMA mode 1 (using DMA data transfers)
viaide0:1:1: lost interrupt
        type: atapi tc_bcount: 32 tc_skip: 0
cd0: transfer error, downgrading to DMA mode 2
wd1(viaide0:1:0): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA data transfers)
cd0(viaide0:1:1): using PIO mode 4, DMA mode 2 (using DMA data transfers)
viaide0:1:1: lost interrupt
        type: atapi tc_bcount: 32 tc_skip: 0
cd0: transfer error, downgrading to PIO mode 4
wd1(viaide0:1:0): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA data transfers)
cd0(viaide0:1:1): using PIO mode 4

-- 

s.