I just installed a new Plextor-760A in my computer, but for some strange reason Ubuntu cannot read most types of discs in it. The only type of discs that do work are DVD-Rs burned with UDF formatting for some odd reason... My other drive on the other hand, which is a Sony DRU-510A, works great. As did the AOpen DUW1616L drive I used to have in the same slot. Additionally, the Plextor drive functions perfectly inside Windows XP, and also functions perfectly inside a VMWare instance running Windows XP as a guest under Ubuntu. The only conclusion I can reach here is that Ubuntu doesn't know how to work with the drive, so I could use some help troubleshooting this.

Ok, after reading this thread I tried ide=nodma as a kernal boot parameter and the drive seems to be funtioning normally. I was also getting dmesg errors that looked something like this:

While this has fixed the problem, disabling DMA for all IDE devices is certainly not an ideal solution. If anyone knows of a better fix for this then please let me know. *Sigh*, now I really wish I'd gotten the SATA version of the drive...

Hi

Not a good solution either, but with the command "hdparm", you can disable dma without disabling it on all disks, so you can disable it for the Plextor and not the harddisks.

The command is "sudo hdparm -d0 device".