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

Stef stef.dev at free.fr
Mon May 11 20:05:33 UTC 2015

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_calib
>>> ra tion.ppm.gz
>>> http://www.rainbow-software.org/linux_files/umax_astra_4450/no_gain_calib
>>> 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...

     you could try to hardcode gain values at the end of gain 
calibration to see if scan is close to be correct.


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