Home › Forums › TWAIN Classic › Weird interaction between TWAIN and WIA DSs for same scanner
- This topic has 10 replies, 4 voices, and was last updated 9 years, 10 months ago by HelgaBajaj.
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Can’t say I’m very hopeful about getting any response from this query 😥 – the forum seems to have degenerated into a spam magnet, signal to noise ratio about 0.05, over the last few months – but nothing ventured, nothing gained.
I have recently been migrating my TWAIN apps and devices to Windows XP. I’ve sorted most matters arising (mostly file access issues relating to admin vs user rights), but one has me stumped. It relates to an Epson Perfection 2480 scanner, which has been my favourite scanner yet for the year or so I’ve been using it. I’ve never found a single issue with it, until now. Here’s the hierarchy of observations.
Epson scanner
As Administrator: apps work OK
As User: apps fail after a somewhat variable period of operation, reporting “Failure to communicate with the scanner”
As User, with WIA disabled: apps work OKTwo other scanners (a Canon and a Umax)
Apps work unconditionallyI tried disabling WIA because I looked at all the files that were being updated during the course of a run and found wiadebug.log, which included loads of repeats of the following lines:
StiLockMgr::RequestLockHelper, device is busy
Device locked , could not get status . HResult=(80210006)I figured that I wasn’t using WIA, and wasn’t going to, so disabling it couldn’t do any harm and might just do some good. And it turned out to solve the problem (though it has spawned other equally unexpected ones).
My question for this forum is: the facts above seem to me to support the hypothesis that the TWAIN and WIA DSs for the Epson are conflicting somehow. Can anyone hazard a guess as to how this might be? Epson say if WIA is responsible, it’s Microsoft’s problem not theirs, and so now I’ve got an open tech support case with Microsoft, and £70 of my own money at stake if they determine it’s not their fault either 🙄
Andy
interesting. I havent noticed any problems running epson scanners on xp as you’re describing. Is this an app you wrote or one that someone else wrote? If you wrote it, couldn’t you include a little more logging to determine the cause? Or if it isn’t one that you wrote, maybe you could test the senerio with different app… But in either case I’m interested in hearing the conclusion.
Hi Gabe,
Are you using your Epson scanners with Admin rights, or User rights? That’s an important distinction – the problem only occurs for Users. And are you repeatedly opening and closing the DS in a single TWAIN session? I bet you aren’t, but that’s what’s doing the damage. Don’t ask me why I have to do this, please – just take it as read!
I wrote the app, but I use EZTWAIN to do all the TWAIN stuff – so I can’t log below the level of the calls that I make to EZTWAIN, and it’s an EZTWAIN call that fails. EZTWAIN has its own log, but it sheds no light either.
Just as I expected, Microsoft and Epson are currently involved in mutual finger-pointing. Me, I’m equivocal – there is evidence that could point either way, or indeed both ways. I just want the problem to be sorted.
Andy
admin or user … tricky question. both? neither… It is run as service using the LocalSystem account. Probably closer to admin than user. I guess I could change the service to run under the users account and re-run the tests, but I wouldn’t run it that way in production just becasue it would lead to more mainenance when the user accounts change.
On the other point, I open and close the ds several times in a session, but I havent seem the problem you’re describing yet. I ran somewhat heavy testing a few months back and our epson did ok. I’m not an epson fan cause their twain implementation is … .. well, I think they could have done a better job, but for the capabilites that they do support, they seem to be consistant.
What did the guys over at Dosadi say about the EZTWAIN logging? And while I’m asking, which library are you using Pro or Classic?
They seem to be more than decent people with an exceptional understanding of twain and they’ve been super helpful in the past.
In fact I think one or two of them frequent this board, helping to answer questions.Did they have any input?
gabe
You’re absolutely right about Dosadi – they’re brilliant.
I’ve just reviewed what I’ve posted about this problem in the Dosadi tech fourm, and it’s fragmented, to say the least. It’s spread across two different topics, one of which is a rather unfocussed plea for ideas, and the other one of which rather gives the impression that turning off WIA solves the problem. Which in one sense it does, but it also causes other problems.
As regards the EZTWAIN log file, I never posted any excerpts from that – I think I had a look myself and found that it didn’t provide any helpful clues. “Failure to open the DS” – yeah, I know, but why?
I think it would probably be a good idea to start a new topic, include a key excerpt from the log file, and be more specific in what I ask. But not at 17:50 on a Friday…!
Andy
Hi Gabe,
Well, one out of three isn’t too bad. I didn’t start a new thread, and I didn’t post an excerpt from the log file, but I was more specific in what I asked:
http://cybermessageboard.purehost.com/d30006555/posting.php?mode=reply&t=515
As you will see, I’ve now succeeded in reproducing the problem using Adobe Photoshop Elements. I don’t suggest you try it yourself, unless you’re very bored 😉 – but it rules out my software and EZTWAIN as the source of the problem – so if you have a TWAIN app where you can easily open and close the DS repeatedly under program control, you might want to have a go on your Epson scanners. You’ll typically need of the order of 100 cycles though.
Andy
ha, unless adobe is using eztwain…
Ha indeed! 🙄 I am going to resist the temptation to run Dependency Walker to make sure …
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