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I have a very weird issue with one of my optical drives at the moment. Currently, I have an old Plextor PX-760A IDE-drive and a Pioneer BDR-206 installed by SATA.

The Pioneer drives works without any problems so far.

The Plextor drive, however, is recognised by the system (HardInfo can even read the firmware details in the storage devices), but I can not open any audio CDs I put in, because if I try to mount them, the error Failed to mount "Audio Disc". Drive /dev/sr0 does not contain audio files. is displayed (after freezing my file explorer and all programs trying to access the CD for a while or until I call up sudo lshw and the error then is displayed. Also, DVDs are not even shown in the file manager when inside the drive, although this is also a DVD drive.

I am also unable to access the media on the cd with any other program, as they will also display error messages.

The output of lshw when a disk is inserted is as follows:

  *-disk:0                
       Beschreibung: SCSI Disk
       Produkt: STORAGE DEVICE
       Hersteller: Generic
       Physische ID: 0.0.0
       Bus-Informationen: scsi@10:0.0.0
       Logischer Name: /dev/sda
       Version: 9744
       Fähigkeiten: removable
       Konfiguration: logicalsectorsize=512 sectorsize=512
     *-medium
          Physische ID: 0
          Logischer Name: /dev/sda
  *-disk:1
       Beschreibung: SCSI Disk
       Produkt: STORAGE DEVICE
       Hersteller: Generic
       Physische ID: 0.0.1
       Bus-Informationen: scsi@10:0.0.1
       Logischer Name: /dev/sdb
       Version: 9744
       Fähigkeiten: removable
       Konfiguration: logicalsectorsize=512 sectorsize=512
     *-medium
          Physische ID: 0
          Logischer Name: /dev/sdb
  *-disk:2
       Beschreibung: SCSI Disk
       Produkt: STORAGE DEVICE
       Hersteller: Generic
       Physische ID: 0.0.2
       Bus-Informationen: scsi@10:0.0.2
       Logischer Name: /dev/sdc
       Version: 9744
       Fähigkeiten: removable
       Konfiguration: logicalsectorsize=512 sectorsize=512
     *-medium
          Physische ID: 0
          Logischer Name: /dev/sdc
  *-disk:3
       Beschreibung: SCSI Disk
       Produkt: STORAGE DEVICE
       Hersteller: Generic
       Physische ID: 0.0.3
       Bus-Informationen: scsi@10:0.0.3
       Logischer Name: /dev/sdd
       Version: 9744
       Fähigkeiten: removable
       Konfiguration: logicalsectorsize=512 sectorsize=512
     *-medium
          Physische ID: 0
          Logischer Name: /dev/sdd
  *-disk:4
       Beschreibung: SCSI Disk
       Produkt: STORAGE DEVICE
       Hersteller: Generic
       Physische ID: 0.0.4
       Bus-Informationen: scsi@10:0.0.4
       Logischer Name: /dev/sde
       Version: 9744
       Fähigkeiten: removable
       Konfiguration: logicalsectorsize=512 sectorsize=512
     *-medium
          Physische ID: 0
          Logischer Name: /dev/sde
  *-cdrom
       Beschreibung: SCSI CD-ROM
       Physische ID: 0.0.0
       Bus-Informationen: scsi@0:0.0.0
       Logischer Name: /dev/cdrom
       Logischer Name: /dev/cdrw
       Logischer Name: /dev/dvd
       Logischer Name: /dev/dvdrw
       Logischer Name: /dev/sr0
       Fähigkeiten: audio
       Konfiguration: status=ready
  *-disk
       Beschreibung: ATA Disk
       Produkt: Crucial_CT256MX1
       Physische ID: 0.0.0
       Bus-Informationen: scsi@2:0.0.0
       Logischer Name: /dev/sdf
       Version: MU02
       Seriennummer: 14400D639780
       Größe: 238GiB (256GB)
       Fähigkeiten: partitioned partitioned:dos
       Konfiguration: ansiversion=5 logicalsectorsize=512 sectorsize=4096 signature=71c8b4c4
  *-disk
       Beschreibung: ATA Disk
       Produkt: WDC WD20EARX-00P
       Hersteller: Western Digital
       Physische ID: 0.0.0
       Bus-Informationen: scsi@3:0.0.0
       Logischer Name: /dev/sdg
       Version: AB51
       Seriennummer: WD-WCAZAE482968
       Größe: 1863GiB (2TB)
       Fähigkeiten: partitioned partitioned:dos
       Konfiguration: ansiversion=5 logicalsectorsize=512 sectorsize=4096 signature=887d0b1d
  *-disk
       Beschreibung: ATA Disk
       Produkt: WDC WD5003AZEX-0
       Hersteller: Western Digital
       Physische ID: 0.0.0
       Bus-Informationen: scsi@4:0.0.0
       Logischer Name: /dev/sdh
       Version: 1A01
       Seriennummer: WD-WCC3F7PV71X8
       Größe: 465GiB (500GB)
       Fähigkeiten: partitioned partitioned:dos
       Konfiguration: ansiversion=5 logicalsectorsize=512 sectorsize=4096 signature=108ce8fb
  *-cdrom
       Beschreibung: DVD writer
       Produkt: BD-RW   BDR-206D
       Hersteller: PIONEER
       Physische ID: 0.0.0
       Bus-Informationen: scsi@6:0.0.0
       Logischer Name: /dev/sr1
       Version: 1.04
       Fähigkeiten: removable audio cd-r cd-rw dvd dvd-r
       Konfiguration: ansiversion=5 status=nodisc

I use this drive rarely, but the strangest thing is that I used this drive to listen to a full album maybe a week ago without any issues, so this does not seem to be a hardware failure, unless the drive broke while sitting safely inside my computer case in that time.

What could be the problem and what can I do to solve this?

Edit: I have found that the drive is able to mount audio discs when a data disc was inserted and read previously. The drive is able to read all files on the data CD and when it is ejected and an audio CD is put it directly after without rebooting, the drive can then mount the audio CD and displays all tracks in the file manager. It can then also be played in any media player without any issues.

The drive seems to be unable to read audio discs before reading data discs after every reboot and still can not recognise DVDs for some reason. I hope this could be a clue to what is causing this issue.

Prototype700
  • 1,120

1 Answers1

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I have found an apparent solution or work-around for the problem by myself, I believe.

While starting the system with a CD inserted in the drive, the kernel messages would constantly display AMD-Vi: Event logged [IO_PAGE_DAULT device=... and other error details, sending the machine into a loop for a few minutes.

I searched for the string online and found out that it appears to be an IOMMU-related error or bug in the Linux kernel. The workaround was to start the machine, enter GRUB by holding Shift while booting, then press e on the standard entry and add iommu=soft in the kernel parameters, e.g. behind quiet splash.

After that, the entry can be added in the same way to the GRUB configuration file by opening a Terminal and entering sudo nano /etc/default/grub and then executing sudo update-grub2.

This, just in case somebody else has a similar issue and needs instructions for a quick fix.

However, I am not entirely happy with this solution, as I did not have problems with any other devices in my system without this kernel parameter and I would like to keep the hardware IOMMU-functionality intact.

The way I understand it, iommu=soft effectively routes all requests through some kind of software memory management interface, which uses up system perfomance (although probably very little) and disables the hardware IOMMU entirely. I would like to understand more about what it actually does, but I wasn't able to find much info on the exact functionality. If someone has a better solution or knows where I can read more about it, please feel free to answer still or link a source for this! Thanks.

Prototype700
  • 1,120