[sane-devel] rts8891: Umax Astra 4450 does not work

[Ondrej Zary]

On Monday 11 May 2015 22:05:33 Stef wrote:
> On 09/05/2015 00:32, Ondrej Zary wrote:
> > On Friday 08 May 2015 21:46:36 Ondrej Zary wrote:
> >> On Friday 08 May 2015 16:17:53 Ondrej Zary wrote:
> >>> On Thursday 07 May 2015 23:32:28 Ondrej Zary wrote:
> >>>> Hello,
> >>>> I just got Umax Astra 4450 (same as 4400 except with UTA?) for a while
> >>>> and tested it with SANE. Unfortunately, it does not work. The lamp
> >>>> turns on and the head moves a bit, then goes back (two times) and the
> >>>> scan ends with these errors:
> >>>>
> >>>> [rts8891] simple_scan: failed to wait for data
> >>>> [rts8891] gain_calibration: failed scan data
> >>>> [rts8891] sane_start: failed to do gain calibration!
> >>>> scanimage: sane_start: Error during device I/O
> >>>
> >>> I've modified sane_start() in rts8891.c to not fail if
> >>> gain_calibration() returns error. It now scans the complete area and
> >>> the output resembles what's in the scanner (black template for UTA use
> >>> with green text) but it's blurry, shifted horizontally (and the gain is
> >>> wrong, of course):
> >>> http://www.rainbow-software.org/linux_files/umax_astra_4450/no_gain_cal
> >>>ib ra tion.ppm.gz
> >>> http://www.rainbow-software.org/linux_files/umax_astra_4450/no_gain_cal
> >>>ib ra tion.log
> >>>
> >>> Looks like there's a problem with the sensor type?
> >
> > Gain calibration fails because dev->left_offset (and thus xstart) is
> > negative. If I set xstart to 4, gain calibration passes (although it's
> > wrong: ends after first pass with 0x1f,0x1f,0x1f).
> >
> > So find_margin() does not work...
>
>      Hello,
>
>      you could try to hardcode gain values at the end of gain
> calibration to see if scan is close to be correct.

The dumps from Windows are very different. I've transferred the register 
settings to sane-rts8891 but with only partial success. 150dpi and 300dpi 
seems to work if I don't touch 0x7a register. 75dpi, 600dpi and 1200dpi are 
broken no matter what I tried.

The experimental patch is available at
http://www.rainbow-software.org/linux_files/umax_astra_4450/umax_astra4450-test.diff

-- 
Ondrej Zary