NEC ND1300A with DMA enabled?

[Christian Kleitsch]

Hello everybody!

has anybody managed to use the NEC ND1300A with DMA enabled?
It seems, that I'm not alone with my problem.
My configuration:
Kernel 2.4.22
dvd+rw-tools 5.13.4.7.4
dvdbackup 0.1.1
M/B ASUS A7V266-E (VIA KT266A + VIA VT8233)
CPU AMD XP 1900+
NEC ND1300A, Rev. 1.08
I updated the M/B BIOS to the latest version (1015beta2). But nothing
changed.
With DMA enabled, both read (dvdbackup) and write (growisofs) operations
freeze the machine after a few seconds (no messages on the console or in
the logs).
It seems, that the machine does not freeze if X (gnome) is
not running. I could at least read  2 Video DVDs and write 2 DVD+RW and 
my machine was still running.

When I turn DMA off (hdparm -d 0 /dev/hdc), dvdbackup and growisofs work
just fine, but my CPU load is pretty high (up to 100%). It seems that
recording DVDs with 4x speed is not possible without DMA.
Another annoying detail: explicitly enabling PIO mode 4
(hdparm -p 4 /dev/hdc) dvdbackup and growisofs freeze the machine again.
After disabling DMA or setting the PIO mode, hdparm -I still shows
umda2 as the current acticve mode:
root:~# hdparm -I /dev/hdc
/dev/hdc:

ATAPI CD-ROM, with removable media
        Model Number:       _NEC DVD_RW ND-1300A
        Serial Number:
        Firmware Revision:  1.08
Standards:
        Likely used CD-ROM ATAPI-1
Configuration:
        DRQ response: 3ms.
        Packet size: 12 bytes
Capabilities:
        LBA, IORDY(cannot be disabled)
        DMA: mdma0 mdma1 mdma2 udma0 udma1 *udma2
             Cycle time: min=120ns recommended=120ns
        PIO: pio0 pio1 pio2 pio3 pio4
             Cycle time: no flow control=120ns  IORDY flow control=120ns
hdparm writes following messages in the log file:
...kernel: hdc: drive_cmd: status=0x51 { DriveReady SeekComplete Error }
...kernel: hdc: drive_cmd: error=0x04
Hints how to enable DMA without freezing the machine or how to reach 4x 
recording speed are welcome.

Regards,
Christian
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