[sane-devel] Error: Canon Pixma MG7550 hangs

Mon Jan 5 21:48:00 UTC 2015

> If the scanner does not work on a USB port it is quite unlikely to work
> over the network: the bjnp network code just carries the USB exchange
> over IP.

I mostly agree, though Rolf asks specifically for the USB trace, because
(as I understood) it differs slightly from the IP traces I had already
submitted.
(fix usb first , then patch it for IP, if need be)

One advice:
Be very paranoid on your test methodology. I looked stupid a couple of
times (sorry Rolf!), because I was fooled by the USB interface and/or the
Canon firmware.
When testing a new patch, I tried some settings in random (DPI ,
colour/black-n-white etc) and reported the success/failures.
BUT the thing is, that the Canon MF8230 firmware can go into bad-mode, when
it has received some strange commands, and the following scans might work
slightly strange for that reason. I was even fooled by the phenomenon, that
scanning a 1 by 1 cm square works, but scanning the whole A4 didn't. (Well
... there WERE some differences between what worked through USB and IP at
this point in time. I'm guessing it was something timing-critical, but I
never dissected that last patch from Rolf which fixed it)

So I started rebooting the scanner whenever I was in doubt.
(disconnect/connect the USB interface plus move Cannon unit from to
"printer mode" and back to "scanner mode" was normally enough)

So what do we do? / What is status?

Since scanning CAN work , one could argue the back-end DOES send all the
necessary+correct commands to the printer.
If timing is the critical parameter (backed by the fact that something as
stupid as enabling IP on the printer-side, suddenly makes it work now and
then), maybe we should try to insert an ugly time-delay before every USB
write? If that changes anything to the better, we can start to hunt down
where it is really necessary, and hopefully find a nicer approach
afterwards?

Martin, are you comfortable with pulling the code out of the GIT
repository, compile , install and experiment with inserting delays?
I think there is something called "SANE interface USB" sanei_usb.c/h. That
was maybe a place to start.

Louis, what is the odds of success for this approach?
:-)

/Troels

2015-01-03 20:43 GMT+01:00 Martin <martin.gu at intergga.ch>:

> Am Samstag, 3. Januar 2015, 11.16:10 schrieb Louis Lagendijk:
> > On Fri, 2015-01-02 at 22:59 +0100, Martin wrote:
> > > Hi Troels
> > >
> > > > *Is it USB3 (on the computer)?
> > >
> > > no, it is USB2
> > >
> > > > *Do you have access to another computer, where you can try it - Does
> it
> > > > work excactly the same strange way ... ?
> > >
> > > No,I don't have access to another computer. But I have also Windows 7
> > > installed. With Windows 7 and the Canon-software it works OK.
> > >
> > > > *Does unit have ethernet connection / can you try that way?
> > >
> > > Yes. With the ethernet connection the printer works. Thus the
> IP-address
> > > below is correct.
> > > But I cannot access the scanner.
> > >
> > >     xsane pixma:MG7500_192.168.0.3
> > >
> > > results in the error message "illegal argument". Same thing with
> > >
> > >     scanimage --help -d bnjp://192.168.0.3:8612
> >
> > Hi Martin
> > If the scanner does not work on a USB port it is quite unlikely to work
> > over the network: the bjnp network code just carries the USB exchange
> > over IP.
> > Anyhow, you can find the name with scanimage -L (but make sure that port
> > 8612 is not blocked by a firewall (see the man-page for sane-pixma in
> > the latest sources from GIT. you need to enable port 8612 for both
> > incoming and outgoing traffic.
> >
> > Louis
>
> Hi Louis
>
> The necessary ports on the firewall are open, yet scanimage -L does not
> find
> the scanner.
>
> But this lead to another discovery:
> I enabled LAN on the MG7550. And although the unit is connected via USB 2
> xsane sometimes works?! But with LAN disabled xsane never works without
> prior
> scanimage -T. And once xsane or scanimage -T failed all succeeding calls
> fail
> until the scanner is switched off and on again.
>
> Log of xsane working:
> [sanei_debug] Setting debug level of pixma to 21.
> [pixma] pixma is compiled with pthread support.
> [pixma] pixma version 0.17.13
> [pixma] pixma_collect_devices() found Canon PIXMA MG7500 Series at
> libusb:001:007
> [pixma] pixma_find_scanners() found 1 devices
> [pixma] pixma_collect_devices() found Canon PIXMA MG7500 Series at
> libusb:001:007
> [pixma] pixma_open(): Canon PIXMA MG7500 Series
> [pixma] *mp150_open***** This is a generation 4 scanner.  *****
> [pixma] [pixma] Reader task id=139772037314304 (threaded)
> Reader task started
> [pixma]
> [pixma] pixma_scan(): start
> [pixma]   line_size=4605 image_size=4895115 channels=3 depth=8
> [pixma]   dpi=300x300 offset=(0,0) dimension=1535x1063
> [pixma]   gamma_table=0x1f201e0 source=0
> [pixma]   threshold=127 threshold_curve=0
> [pixma]   ADF page count: 0
> [pixma] OUT  T=58.770 len=288
> [pixma]  00000000:3c 3f 78 6d 6c 20 76 65  72 73 69 6f 6e 3d 22 31
> [pixma]  00000010:2e 30 22 20 65 6e 63 6f  64 69 6e 67 3d 22 75 74
> ...
> Log of xsane not working:
> pixma] pixma_collect_devices() found Canon PIXMA MG7500 Series at
> libusb:001:008
> [pixma] pixma_find_scanners() found 1 devices
> [pixma] pixma_collect_devices() found Canon PIXMA MG7500 Series at
> libusb:001:008
> [pixma] pixma_open(): Canon PIXMA MG7500 Series
> [pixma] *mp150_open***** This is a generation 4 scanner.  *****
> [pixma] INTR T=1.249 len=32
> [pixma]  00000000:00 00 00 01 00 00 00 00  00 00 00 00 00 00 00 00
> [pixma]  00000010:00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
> [pixma]
> [pixma] Sending time: '15/01/03 15:32'
> [pixma] OUT  T=1.250 len=36
> [pixma]  00000000:eb 80 00 00 00 00 00 00  00 00 00 00 00 00 00 14
> [pixma]  00000010:31 35 2f 30 31 2f 30 33  20 31 35 3a 33 32 00 00
> [pixma]  00000020:00 00 00 53
> [pixma]
> [pixma] IN   T=21.251 len=-9
> [pixma]   ERROR: ETIMEDOUT
> [pixma]
> ...
>
> Martin
>
>
> --
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