During SCSI bus enumeration A/UX sends a MODE SENSE command to the CDROM with
the DBD bit unset and expects the response to include a block descriptor. As per
the latest SCSI documentation, QEMU currently force-disables the block
descriptor for CDROM devices but the A/UX driver expects the requested block
descriptor to be returned.
If the block descriptor is not returned in the response then A/UX becomes
confused, since the block descriptor returned in the MODE SENSE response is
used to generate a subsequent MODE SELECT command which is then invalid.
Add a new SCSI_DISK_QUIRK_MODE_SENSE_ROM_USE_DBD quirk to allow this behaviour
to be enabled as required. Note that an additional workaround is required for
the previous SCSI_DISK_QUIRK_MODE_PAGE_APPLE_VENDOR quirk which must never
return a block descriptor even though the DBD bit is left unset.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20220622105314.802852-5-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
f43c2b94cd