DVD read problem (automount)



I have a NEC 4551A and some problems with certain dvds, even if they were burned with low speed.
I thought it was linux fault, so I upgraded default openSuSe kernel to 2.6.20, threw out unnecessary stuff and compiled just what I needed (I also unchecked generic IDE drivers from it).

But still automount didn’t work since dvdrom is reporting inserted dvds as bad:

Mar 8 22:36:10 linux kernel: hdc: media error (bad sector): status=0x51 { DriveReady SeekComplete Error }
Mar 8 22:36:10 linux kernel: hdc: media error (bad sector): error=0x34 { AbortedCommand LastFailedSense=0x03 }
Mar 8 22:36:10 linux kernel: ide: failed opcode was: unknown
Mar 8 22:36:10 linux kernel: ATAPI device hdc:
Mar 8 22:36:10 linux kernel: Error: Medium error – (Sense key=0x03)
Mar 8 22:36:10 linux kernel: (reserved error code) – (asc=0x02, ascq=0x00)
Mar 8 22:36:10 linux kernel: The failed “Read 10” packet command was:
Mar 8 22:36:10 linux kernel: "28 00 00 00 00 10 00 00 02 00 00 00 00 00 00 00 "
Mar 8 22:36:10 linux kernel: end_request: I/O error, dev hdc, sector 64
Mar 8 22:36:10 linux kernel: Buffer I/O error on device hdc, logical block 8

But they are readable if I mount them manually:

sudo mount /dev/hdc /mnt

So it is clearly not a linux problem, it is automount precaution to void mounting when bad media is detected to possibly avoid dvdrom deadlocks or something (like when it is trying to read dvd for long time and you cannot eject media).

I was busting my head a loooooooong time with this and today I spontaneously discovered something. I decided to take a look at this problem again, so I reached to so called “faulty dvds” and started to test them. But now they were working. Every single one of them was working!
However copying was slower than declared dvdrom speed, it was about 4x. And then I remembered that I previously burned a dvd with 4x speed - so I thought that my dvdrom somehow got stuck on this read speed as well. To be sure I did a reboot and voila - dvds were not being automounted again.
I cannot force nec dvdrom to read dvds with lower speed, since it will completely ignore this:

hdparm -E X /dev/hda

and so I cannot do further tests. I tried again by burning another dvd with lower speed, but it didn’t got stuck with it.
I tested same dvds on another drive, a liteon sohw812s and it doesn’t have this problems. Also one of my friend owning a nec 3xxx series called me last time that has some problems with some dvds and when I checked dmesg I saw it was the same problem as mine.

I think this problem occurs only on multisession discs, when you insert them you can hear a shor buzz after spin-up (like the lens is being moved all the way).

Is it possible to fix this with firmware? Or is this a hw issue?