Can't set DMA mode for DVD/CDRW on Compaq nc6400

[dandv]

I have a new Compaq nc6400 (the widescreen version) and DVD playback by VideoLAN VLC or The KMPlayer is very choppy. Process Explorer indicates 40% of the CPU is used by hardware interrupts. The machine has a Matsushita UJDA775 DCD/CDRW drive.

I went to the Primary IDE Channel in Device Manager and saw that sure enough, the Transfer Mode was set to PIO Only. I set it to DMA if available, and rebooted, but after the reboot, the Current Transfer Mode was still PIO Only.

How can I get the DVD in this laptop to run in DMA mode?

Thanks,
Dan

 

[g-paw]

Check the BIOS

 

[dandv]

Checking the BIOS revealed that DMA Transfers were enabled. As a sanity check, I disabled them, rebooted, but the DVD drive was still in PIO Only mode.

I eventually fixed the problem in a very unusual way. Check this out:

I downloaded DVDFab (http://www.dvdfab.com) and noticed that on its General settings page, it had a button labeled "Reset DMA". Clicked that, was asked to reboot, and BINGO - the transfer mode is now "Multi-Word DMA Mode 2"

Yay for DVDFab!

Hope this helps,
Dan Dascalescu

 

[g-paw]

Good to know