0003037: AHCI Mode at Virtualbox hangs on OS2CDROM.DMD
Bug opened in the eComStation bugtracker. Customer pointed to this bug to follow it.
Running at:
- VxT capable machine i3 with Windows 7 64bits
- VirtualBox 4.0.6 (Windows 7 Host)
When changing the settings on the Virtual Machine Storage (Screenshot 1) to use AHCI HDD and CDROM the boot procedure hangs on OS2CDROM.DMD
This bug was reported the eComStation bugtracker
The Boot settings get change to Virtual Machine (Screenshot 2) and turn AHCI mode (Screenshot 3).
- It hangs at OS2CDROM.DMD (Screenshot 4)
- It hangs at JJCDROM.DMD (Screenshot 5)
- It hangs at old OS2CDROM.DMD (Screenshot 6)
The workarround is to do not use AHCI SATA DRIVERS on VirtualBox, but this bug report can be usefull to fix OS2AHCI and OS2CDROM.
This has been fixed in version 1.19. The problem is originall caused by VirtualBox's emulation of a CDROM drive on the AHCI controller: If there's an error in a specific command (I believe it was a mode sense command), the current command index register in the AHCI controller is not set correctly. As a result, OS2AHCI couldn't locate the failing command and request a sense buffer. Instead, it treated the failing command like any other command in the queue and simply requeued it. Since there was no retry counter, this would go on indefinitely and the system would hang.
While the problem lies inside VirtualBox, OS2AHCI should never get into such a situation. After all, there could be faulty hardware with similar problems. Thus, a retry counter was implemented and commands in the queue will never be retried more than 3 times before they are returned with a generic error code.
Thanks,
--Christian