On Wednesday 18 June 2003 19:30, you wrote: > 0) None of this generation of Microtek scanners supports SCSI > disconnect. Disconnect needs to be disabled for the scanner device > (if not the whole bus), and you should expect the scanner to > monopolize the entire bus during a scan.
I really don't understand SCSI much. FreeBSD gives me still "unexpected disconnect" with my scanner, after I switched off "disconnection" in my controller's BIOS. > 1) The firmware in the earlier Microtek scanners is particularly > brain-dead with regards to timeouts like this. Even worse, I have > pretty extensive documentation from Microtek --- *but every scanner > deviates from the documented behavior in some important way*. Ugh. Yes. It is a quite "cheap" scanner and came with a separate ISA SCSI-1 controller. Now I'm using one with a Symantec chipset (Tekram DC390/UW). The scanner is attached to external UW bus. I wonder if it is really correct to connect it like this, but IT WORKED earlier (1 or 2 years ago?) on Debian, so it should not be a problem. > The Linux > drivers are trying to be clever, but they assume that *every* device > is SCSI-2, and since the codes do not conform to SCSI-2, they get > squashed. > > Probably, FreeBSD is doing the same thing. What both OS's > *should* do is just pass the poor sense codes up to the sense handler > installed by the backend, which should be smart enough to deal with > them. Instead, the sense handler always gets called with a bunch of > zeros! Well, if I only had time to look at FreeBSD SCSI architecture, I would try to help. I wonder why they would remove information from the sense responses. > it is unclear which commands can be sent during that delay, if > that delay can be polled (i.e. ask the scanner if it is ready) or if > it must be guessed, etc, etc. There is a possibility to compile the FreeBSD kernel with CAM debugging. This produces LOTS of information (see: man camcontrol(8)). With just a bit luck, there might be some useful information about the scanner's behavior. > I'll start rummaging through my notes. I'm recollecting now that I > had a quick fix for this a couple of months ago --- but it was too > late for the release back then, and then I got really really busy. I don't know how many people are using old Microtek scanners. If it is too much trouble, simply forget it. Martin
