[sane-devel] Problems with Canon MP990 transparency unit

[Guillaume Courtois]

Hi Rolf,

I've just seen I sent my first response to you but not the list, sorry 
about that (but it contained nothing interesting in fact).

I made some progress today, color shifting seem ok and I don't have the 
white columns anymore.
I'll have to give a clean patch to the list for that, but first I have 
to solve my last problem, which is underrun.

I tried to find the source of that problem but with no luck until now. 
It seem to happen only with TPU unit, strange ?

Here is the result at 1200 dpi :

pixma] **mp810_fill_buffer***** end of image *****
[pixma] WARNING:image size mismatches
[pixma]     859431936 expected (14032 lines) but 222452736 received 
(3632 lines)
[pixma] pixma_read_image(): completed (underrun detected)

(in debug :
[pixma] *mp810_fill_buffer***** moving 504704 bytes into buffer *****
[pixma] *mp810_fill_buffer***** 507904 bytes received by 
read_image_block *****
)

and at 600 dpi :

[pixma] **mp810_fill_buffer***** end of image *****
[pixma] WARNING:image size mismatches
[pixma]     214857984 expected (7016 lines) but 111226368 received (3632 
lines)
[pixma] pixma_read_image(): completed (underrun detected)

(in debug :
[pixma] *mp810_fill_buffer***** moving 260096 bytes into buffer *****
[pixma] *mp810_fill_buffer***** 245760 bytes received by 
read_image_block *****
)

Buffer size seem to be twice the size when raising the resolution. 
Shouldn't it be 4 times bigger ?

I hope you have an idea here because my head is exploding...

Thanks !

Bye.

Le 27/10/2014 16:57, Rolf Bensch a écrit :
> Hi Guillaume,
> 
> If you want to dig into the source code, you can look here:
> 
> file: pixma_mp810.c
> function: post_process_image_data()
> 
> It's possible that post processing image data is broken. Please check
> these git commits:
> b4bb0062c5cbb77c895b439b5f47e70b506305b1 (2013-01-11 16:37:00) and
> 1da5bcc2aa16a6382e5bd78a47cb3ec222a9aafc (2012-01-15 03:48:19)
> 
> Many thanks for your help.
> 
> Cheers,
> Rolf
> 
> 
> Am 19.10.2014 um 15:20 schrieb Guillaume Courtois:
>> 
>> Hi guys,
>> 
>> I'm currently trying to make the TPU correctly work on my MP990
>> scanner. It seems like there are shifting problems both in datas and
>> in the 3 colors (which seem to be 2 separate issues, but not sure).
>> 
>> I'm currently testing on my debian SID with sane GIT version, but I
>> have tested packages from SID and made tests on a Mint 17 netbook
>> also. All seem to give the same results.
>> 
>> It seems like datas are not shifted in 300 dpi but are more and more
>> shifted when you choose higher resolutions (600, 1200, 2400 dpi).
>> 
>> I'm happy to provide pictures if you want to see what it gives, but
>> that gives vertical black stripes on the captured picture.
>> 
>> Here is the output of xscanimage with some debug activated :
>> 
>> Here is the 300 dpi correct scan :
>> 
>> [pixma] pixma_scan(): start
>> [pixma]   line_size=3378 image_size=9674592 channels=3 depth=16
>> [pixma] Reader task id=140539733346048 (threaded)
>> [pixma]   dpi=300x300 offset=(780,88) dimension=563x2864
>> [pixma]   gamma_table=0xd939e0 source=2
>> [pixma]   threshold=127 threshold_curve=0
>> [pixma]   ADF page count: 0
>> [pixma] Setting non-blocking mode
>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>> [pixma] Lamp status: 3 , timeout in: 19
>> [pixma] pixma_read_image():completed
>> [pixma] Reader task terminated
>> [pixma] Reader task started
>> [pixma] Reader task id=140539733346048 (threaded)
>> 
>> Here is the not-so-correct 1200 dpi scan :
>> 
>> [pixma] pixma_scan(): start
>> [pixma]   line_size=13938 image_size=67376292 channels=3 depth=16
>> [pixma]   dpi=1200x1200 offset=(282,446) dimension=2323x4834
>> [pixma]   gamma_table=0xd939e0 source=2
>> [pixma]   threshold=127 threshold_curve=0
>> [pixma]   ADF page count: 0
>> [pixma] Setting non-blocking mode
>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>> [pixma] Lamp status: 3 , timeout in: 19
>> [pixma] WARNING:image size mismatches
>> [pixma]     67376292 expected (4834 lines) but 44044080 received (3160
>> lines)
>> [pixma] pixma_read_image(): completed (underrun detected)
>> 
>> As you can see, mismatch and underrun tells me I have to dig around 
>> that.
>> 
>> Also, it seems like data coming from the preview window is
>> mis-interpreted : I have to pick a smaller and decaled window in order
>> to get the actual correct part of the scan I want to have (I don't
>> know if I'm pretty clear on that one ?).
>> 
>> I'm still digging into the code to see if I can correct that but if
>> you guys could point me to the right direction, that would save me
>> lots of time.
>> 
>> Thanks for your attention, keep up the nice work on sane !
>> 
>> Bye.
>> 
>>