Problem with Mandrake 9.2 and LG CD-ROM drives solved

October 28, 2003

Liggy used our news submit to tell us about this follow-up to an earlier story that indicated LG CD-ROM drives were rendered useless by Mandrake 9.2. The kernel that comes shipped with Mandrake Linux 9.2 and early updates would send a FLUSH_CACHE command to the drive which would make the drive inoperable by overwriting its firmware. Unfortunately, many Dell computers (possibly others) come with these CD-ROM drives. Currently, it is not believed to affect DVD-ROM/R/RW drives and some CD-RW drives; but this all depends entirely upon the firmware on the device.

The problem was that the kernel would send a FLUSH_CACHE command to the LG CD-ROM drive which would make the drive inoperable by overwriting its firmware. This is because LG CD-ROM drives are not compliant with the ATAPI specification.

The specification does not require an implementation of the FLUSH_CACHE command in the driver, and returning an error (or doing nothing) would have been the correct behaviour for the drive. Likewise, reusing a command is against the specification and LG has reused the FLUSH_CACHE command to modify the firmware of the drive, but they are unwilling to disclose exactly what the command does. This FLUSH_CACHE command is supposed to be supported only by CD-RW or DVD-RW devices; the LG-based CD-ROM devices are understanding this command as the UPLOAD_FIRMWARE command.

A new kernel (2.4.22-21mdk) has been released that fixes this problem in the kernel, although the CD-ROM devices are still not up to specification. New CDs and ISOs will be available shortly to correct these problems; they will come with the new kernel.

If an updated firmware for your CD-ROM is available from LG, you are encouraged to apply the firmware update prior to installing Mandrake Linux 9.2. Unfortunately, if the drive becomes inoperable, currently only the manufacturer is able to fix it.

Thank you for the submittal Liggy.

Source: mandrakelinux.com