Re: simple-scan fails with Canon LiDE 300--except as root
On Sat 09 Jan 2021 at 03:53:28 +0000, Dr. Jennifer Nussbaum wrote:
> Just to clarify what someone else in the thread asked about, the user
> I'm running this under _does_ appear in the scanner group.
For what you wish to achieve, being a member of the scanner group is
completely unnecessary. See
https://wiki.debian.org/Scanner
> On Friday, January 8, 2021, 07:07:40 PM EST, Brian <ad44@cityscape.co.uk> wrote:
> On Fri 08 Jan 2021 at 17:28:16 -0500, Jen Nussbaum wrote:
>
> >> When I run simple-scan, it detects the printer and announces itself
> >> ready to go, but when I try to scan anything, I get the message
> >> "Failed to scan Unable to connect to scanner". I Googled for anything
> >> related to this; there's a bunch of stuff on Ubuntu and Mint forums
> >> about purging the "ippusbxd" package, but this isn't on Debian.
> >
> > ippusbxd is certainly not on Debian but ipp-usb is. See the wiki.
>
> Yes, and I do have that; the point was just that the solution that
> worked onMint (to remove ippusbxd and install ipp-usb) isn't relevant
> here.
ipp-usb is relevant insofar as it enables the sane-escl and sane-airscan
backends to be used for scanning.
> >> I then ran simple-scan with the debug flag, and at the moment I try to
> >> initiate a scan, I got:
> >>
> >> [+20.83s] DEBUG: simple-scan.vala:1817: Requesting scan at 150 dpi from device 'escl:http://127.0.0.1:60000'
> >> [+20.83s] DEBUG: scanner.vala:1683: Scanner.scan ("escl:http://127.0.0.1:60000";, dpi=150, scan_mode=ScanMode.GRAY, depth=2, type=single, paper_width=0, paper_height=0, brightness=0, contrast=0, delay=3000ms)
> >> [+20.83s] DEBUG: scanner.vala:828: Processing request
> >> [+20.83s] DEBUG: scanner.vala:889: sane_open ("escl:http://127.0.0.1:60000";) -> SANE_STATUS_NO_MEM
> >> [+20.83s] WARNING: scanner.vala:893: Unable to open device: Out of memory
> >
> > Nothing about the pixma backend (driver)?
>
> pixma only appears during the startup:
> [+7.62s] DEBUG: scanner.vala:353: Device: name="pixma:04A91913_47A8A4"
> vendor="CANON" model="CanoScan LiDE 300" type="multi-function
> peripheral"
>
> > Just to confirm your experience, what happens with scanning with
> >
> > simple-scan "pixma:04A91913_47A8A4"
>
> This fires up simple scan, and when I click on "scan" it scans the
> document successfully.
I would not expect this to hapen when ipp-usb is active, which it is.
See
https://wiki.debian.org/CUPSDriverlessPrinting
> > and
> >
> > simple-scan "escl:http://127.0.0.1:60000";
>
> This does _not_ work; the response here is the same as when I run it
> normally, i.e. the "Unable to contact scanner" error.
sane-escl is designed to work with an active ipp-usb. This may be a bug
in the backend.
> >> I don't know why I tried this, but I then ran simple-scan as root,
> >> and...it worked perfectly.
> >
> > I do not understand why this should be so. Do both the previous commands
> > work as root?
>
> The "pixma" version worked as root, as it did as the regular user.
> Curiously, the "escl" version did not work as root,even though when I
> run simple-scan without any arguments, it did work as root.
At this site, neither simple-scan nor xsane opens a display when run as
root.
> > > I'm bewildered by this--any idea what I should be looking at?
> >
> > Yes; there is a possible solution. Give what you get for
> >
> > lsusb -v | grep -A 3 bInterfaceClass.*7
>
> ---$ lsusb -v | grep -A 3 bInterfaceClass.*7Couldn't open device, some information will be missing bInterfaceClass 7 Printer bInterfaceSubClass 1 Printer bInterfaceProtocol 4 iInterface 0 can't get debug descriptor: Resource temporarily unavailableCouldn't open device, some information will be missingCouldn't open device, some information will be missing-- bInterfaceClass 7 Printer bInterfaceSubClass 1 Printer bInterfaceProtocol 4 iInterface 0 Couldn't open device, some information will be missingCouldn't open device, some information will be missingcan't get debug descriptor: Resource temporarily unavailableCouldn't open device, some information will be missing---
> (The "Couldn't open device" line was repeated multiple times wherever
> it appeared;I deleted it here for brevity.)
"bInterfaceProtocol 4" indicates that the Canon LiDE 300
understands the IPP-over-USB protocol.
> > and
> >
> > systemctl list-units "ipp-usb*" | grep service
>
> ---$ systemctl list-units "ipp-usb*" | grep service ipp-usb.service loaded active running Daemon for IPP over USB printer support---
Indicates that the IPP-over-USB protocol is being used.
Install sane-airscan and give
scanimage -L
and
airscan-discover
--
Brian.
Reply to: