Hi Wolfram, Sorry for not chiming in earlier.
I have been involved with development of the third-party epkowa and utsushi backends for many years. A lot of the protocol is documented in the code for the utsushi backend via doxygen source comments. See https://gitlab.com/utsushi/utsushi/-/tree/master/drivers/esci # I guess I could add a job to publish the documentation in a more # accessible format via GitLab Pages. Please submit an issue if you # would like that. Remaining comments inlined. Wolfram Sang writes: > Hiya, > >> a) The scanner reports level "B8". For "B8", allowed brightness levels are in >> the -4..3 range. However, my scanner returns -EINVAL for -4. To avoid >> that, >> I guess I need to check the model name and adapt the range accordingly? Only the following values are documented* -3, -2, -1, 1, 2, 3. Yes, 0 is not documented as far as I know. > Fixed with !529. > >> >> b) It seems to me that set_focus is not working for this model because >> e2_set_extended_scanning_parameters() says "/* XXX focus */" and no byte >> in >> the buffer is filled with the focus value. Probably the location is >> unknown? >> And I'd need to snoop Windows USB traffic to (hopefully) figure it out? There is no documented position that I know of but there is still space where it might be set. > Fixed with !530. > >> >> c) 'focus' has only two options. 0mm and 2.5mm. The hex values are 0x19 >> apart. >> That being dec 25, it is tempting to try inbetween values. But I assume >> I'd >> need some evidence that those values are "officially OK" somehow? There are two documented values: 0xff for autofocus and 0x40 for setting it to the glass plate. Other values appear to be allowed. > This and also autofocus added with !531. If someone has comments, I am > honestly looking forward to hear them. I am still new to the project. I'll have a look at the merge requests and comment there. > The only question left for me now: Should focus/autofocus settings > really have CAP_ADVANCED? That's debatable indeed but I'd say CAP_ADVANCED is appropriate for most users. Hope this helps, -- Olaf Meeuwissen, LPIC-2 FSF Associate Member since 2004-01-27 GnuPG key: F84A2DD9/B3C0 2F47 EA19 64F4 9F13 F43E B8A4 A88A F84A 2DD9 Support Free Software https://my.fsf.org/donate Join the Free Software Foundation https://my.fsf.org/join
