In above Dmesg generated using Parallels build 1970, ata_piix driver is correctly recognising and configuring emulated DVD/CDROM drive.
Using Parallels build 3186, ata_piix driver is not recognising the emulated DVD/CDROM drive, and it is instead erroring as shown in the previously attached Parallels screendump. So, two separate issues: 1. A change in the hardware emulation by Parallels has broken ata_piix. 2. Previous versions of the kernel (prior to 2.6.20-12) install a driver that correctly recognises the emulated DVD/CDROM driver in the Parallels build 3186. This may be related to changelog comment: "piix: Fix typo that allowed this module to override ata_piix.". -- Parallels Desktop for Mac Optical Drive not recognized https://launchpad.net/bugs/95830 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs