[sane-devel] escl backend not working with HP ScanJet Pro 4500 fn1[99F5CD] adf, platen scanner

[Karl Weber]

Hi,

this time it should indeed be an error in the escl backend. I downloaded and 
installed the airscan backend and this seems to work, first tests have been 
successful with Flatbed, ADF and 'ADF Duplex'. (The homepage of airscan 
explicitly states that my scanner is supported.)

If you are interested, I would assist you in locating and fixing the error in 
the escl backend.

Regards,
Karl

On Montag, 3. Juli 2023 11:37:56 CEST Karl Weber wrote:
> Hi,
> 
> you might remember that I am having trouble scanning from HP ScanJet Pro
> 4500 fn1 with the hpaio backend when using ADF or Duplex as source, but not
> when scanning from the Flatbed.
> 
> Since this scanner supports AirPrint (according to the manual), I tried the
> escl backend as well, but it does not work at all, not even when scanning
> from the Flatbed. My understanding, however, is, that this should work. Am
> I right?
> 
> First, the scanner is recognized with both backends:
> 
> scanimage -L
> device `escl:http://192.168.5.20:8080' is a HP ScanJet Pro 4500 fn1[99F5CD]
> adf,platen scanner
> device `hpaio:/net/hp_scanjet_pro_4500_fn1?ip=192.168.5.20&queue=false' is a
> Hewlett-Packard hp_scanjet_pro_4500_fn1 all-in-one
> 
> When using escl it supports even more options then when using the hpaio
> backend, which already is an advantage for the ecsl backend. (As shown by --
> help.)
> 
> When testing the scanner with the -T option I get the following error
> 
> scanimage -T -d 'escl:http://192.168.5.20:8080'
> Output format is not set, using pnm as a default.
> scanimage: rounded value of br-x from 215.9 to 215.9
> scanimage: rounded value of br-y from 355.6 to 355.6
> scanimage: sane_start: Invalid argument
> 
> When debugging with SANE_DEBUG_ESCL=150 SANE_DEBUG_DLL=100  scanimage -v -v
> -v -T -d 'escl:http://192.168.5.20:8080' 2>xxx.log
> 
> the log contains the following part
> 
> [11:24:25.215061] [escl] Create NewJob : /
> [11:24:25.215284] [escl] escl_curl_url: URL: http://192.168.5.20:8080/eSCL/
> ScanJobs//NextDocument
> [11:24:25.215349] [escl] Before use hack
> [11:24:25.215378] [escl] After use hack
> [11:24:31.188234] [escl] eSCL scan : [Success]  real read (11868)
> [11:24:31.194000] [escl] Error :
> poppler_document_new_from_data[11:24:31.194025] [escl] 2-Size Image (0)[0x0|
> 0x0]
> scanimage: sane_start: Invalid argument
> [11:24:31.194036] [dll] sane_cancel(handle=0x563d201082a0)
> [11:24:31.194041] [escl] escl sane_cancel
> [11:24:31.194133] [escl] escl_curl_url: URL: http://192.168.5.20:8080/eSCL/
> ScanJobs//NextDocument
> 
> Could you give me some help here? I would prefer to use the escl backend
> over the hpaio backend, since the former offers more options than the 
> latter. However the former does not seem to work at all.
> 
> Thanks in advance!
> Best regards
> Karl