[Qemu-devel] scsi-bus: Add support for SCSI scanners

[Jarkko Lavinen]

I have been trying to get Minolta Multi Pro SCSI film scanner working
with Qemu in Linux and WinXP guests.  With Linux guest and virtio
interface the scanner works out of the box. Unfortunately I haven't
been able to find virtio SCSI driver for Win XP.

With Linux guest and pvscsi driver additional patches are needed to
add support for some missing commands. The same patches are also
needed with WinXP guest with virtual LSI SCSI adapter drivers.

With these patches I am able to do index scan, frame selection,
prescan, focus, scanner calibration,main scan (35mm and medium format)
and do the transport lockup. What is still missing is the real
implementation of REQUEST SENSE command with extra bytes which the
scanner application use with focusing.

Few times the scans start return nothing but black in XP but native
Vuescan in Linux works just right and I have to restart the scanner to
fix this.

I've also seen soft lockups while scanning with Test Unit Ready / Mode
Sense in loop with kernel watchdog nagging. Could be that too verbose
SCSI debugging is choking the system. I haven't touched the kernel
(4.4.14) only written 022000" or 022022 (not the octal number but
decimal value) to /proc/sys/dev/scsi/logging_level.

But these patches are still a proof of concept. I am able to use the
SCSI scanner with virtual LSI adapter from Qemu with XP or Linux guest
and and almost everything works. With VMware and VirtualBox not much
or almost nothing works.

Jarkko Lavinen

0001-scsi-bus-Use-correct-transfer-lengths-for-common-SCS.patch
Description: Text Data

0002-scsi-bus-Add-SCSI-scanner-support.patch
Description: Text Data