View Full Version : Out of options enabling DMA mode on a DVD-drive

13th June 2007, 02:28 AM
Hey guys.. now that my DVB card is working beautifully and my server's hooked up in glorious 1080i to my new TV I decided it'd be great to watch some DVDs on it - until I tried it.

I'd imagine you're familiar with DMA mode on drives and their effects on DVD playback, and after some googling, tweaking and experimenting I guess I am too. Here's my setup, and what's going on so far:

The DVD drive is a Pioneer DVR-108 (/dev/hdc) and is on a shared IDE channel with a hard drive (/dev/hdd). The other IDE channel is being used by my other drive, which is SATA but from what I gather has been emulated on the primary IDE channel (it took some fiddling to get everything working on this motherboard - when I saw it had two IDE channels and four SATA ports I stupidly thought they might all work together). There's no way to prevent this setup at the moment (I really need to replace that IDE HDD with a SATA one, but I can't afford to for a few weeks yet).

Using the hdparm command to set DMA mode has been entirely unsuccessful. The only way I've actually managed to enable DMA mode so far has been to set it on the entire channel by adding the boot option "combined_mode=libata", which then does something to prevent the attached hard drive detecting. Judging by the fact my DVD drive becomes /dev/scd0 I'd imagine it somehow reads it as a SCSI device (am I reading that correctly?) but has some real trouble treating the attached hard drive in the same way. This is a slight problem, as this drive has all my network shares :(

God my DVDs looked good with that config though.

After a lot of googling for seemingly-relevant but ne'er successful results I come to you to waste your time on my problem. Anybody had the same problem?
If there is no way to do it on my current setup, would I have better success with a SATA DVD drive, or will the apparent IDE-channel emulation on my motherboard mean I'll run into the same problems but on a different channel?