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SimulPiscator / AirSane

Publish SANE scanners to MacOS, Android, and Windows via Apple AirScan.
GNU General Public License v3.0
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no further scan possible after canceling the preview scan in AIC #41

Closed meiser79 closed 3 years ago

meiser79 commented 3 years ago

Hi,

while AIC scanned the preview, I pressed the cancel button. After this, I couldn't scan anymore. I had to power-off and power-on my scanner. I own a Brother DCP-1510 which uses the brother4 SANE driver (deb package version 0.4.9-1), running on Ubuntu 20.04.

The log shows which indicates that airsaned "hangs" at _saneopen(brother4:bus1;dev2)

document format requested: image/jpeg document format used: image/png using color gamma of 0.555555 sane_init(nullptr, nullptr) sane_open(brother4:bus1;dev2) -> 0x7fd4c001cbc0 [mode] := "24bit Color" -> reload options [source] := "FlatBed" [resolution] := 100dpi [tl-x] := 0mm [tl-y] := 0mm [br-x] := 212mm [br-y] := 356mm sane_start(0x7fd4c001cbc0) with options: [br-x] = 211.881mm [br-y] = 355.567mm [mode] = "24bit Color" [resolution] = 100dpi [source] = "FlatBed" [tl-x] = 0mm [tl-y] = 0mm sane_cancel(0x7fd4c001cbc0) -> pressed cancel during preview scan sane_close(0x7fd4c001cbc0) sane_exit() document format requested: image/jpeg document format used: image/png using color gamma of 0.555555 sane_init(nullptr, nullptr) sane_open(brother4:bus1;dev2)

Thanks in advance for having a look. Best regards, meiser

SimulPiscator commented 3 years ago

I think I understand why this happens (though IMHO the brother backend should handle this situation more gracefully). It will take me a few days (or weeks) before I have time to fix it, I will let you know.

SimulPiscator commented 3 years ago

I added a call to sane_cancel() that might have been missing. The SANE docs are not very clear about how to properly abort a scan. Maybe it works for you now -- it works for me with the genesys backend as it did before.

meiser79 commented 3 years ago

Sorry to say, the behaviour is still the same. AirSane sends a lot of "503 Service Unavailable".

SimulPiscator commented 3 years ago

I did not get similar bug reports from users with other backends, so I tend to see this as a bug in the brother4 backend. AirSane closes the backend properly, this should not leave the device in an undefined state.

meiser79 commented 3 years ago

I can stop a preview scan in xscanimage, and afterwards start a new preview scan (scanner connected via saned). So I have the impression that the issue is not brother4 backend related.

SimulPiscator commented 3 years ago

Whatever the reason, I'm sorry to say I have no idea how to fix this issue.

meiser79 commented 3 years ago

When using the SANE airscan backend with xscanimage, cancelling the preview scan also brings the scanner in the undefined state.

The debug output shows:

Error: Failed restore value of option tl-x: Invalid argument.
Error: Failed restore value of option tl-y: Invalid argument.
Error: Failed restore value of option br-x: Invalid argument.
Error: Failed restore value of option br-y: Invalid argument.

Here's the full debug log: xscanimage-airscan-backend.txt

Maybe this helps.