scanner seen by sane-find-scanner but not by scanimage

doublehp · 02-26-2019, 08:11 AM

After boot:

Code:

# lsusb | grep He
Bus 003 Device 002: ID 03f0:0605 Hewlett-Packard ScanJet 2200c

# sane-find-scanner

  # sane-find-scanner will now attempt to detect your scanner. If the
  # result is different from what you expected, first make sure your
  # scanner is powered up and properly connected to your computer.

  # No SCSI scanners found. If you expected something different, make sure that
  # you have loaded a kernel SCSI driver for your SCSI adapter.

found USB scanner (vendor=0x03f0 [Hewlett-Packard], product=0x0605 [HP ScanJet 2200C], chip=LM9832/3) at libusb:003:002
  # Your USB scanner was (probably) detected. It may or may not be supported by
  # SANE. Try scanimage -L and read the backend's manpage.

  # Not checking for parallel port scanners.

  # Most Scanners connected to the parallel port or other proprietary ports
  # can't be detected by this program.

# scanimage -L

No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).

$ scanimage -x 10 -y 10 --warmup-time 1 --lamp-off-at-exit=no
scanimage: no SANE devices found

After unpluging and repluging USB cable:

Code:

# lsusb | grep He
Bus 003 Device 005: ID 03f0:0605 Hewlett-Packard ScanJet 2200c
# scanimage -L
device `plustek:libusb:003:005' is a Hewlett-Packard Scanjet 2200c flatbed scanner
$ scanimage -x 10 -y 10 --warmup-time 1 --lamp-off-at-exit=no
P6
# SANE data follows
19 19
255

Is there a soft way to make scanner usable after boot without needing physical action ? For various reasons, my usb-core driver is in kernel, so can't unload it.

Similar issue here:
https://www.linuxquestions.org/quest...age-no-840368/

hazel · 02-26-2019, 01:37 PM

I had a similar problem with my Canoscan, which also uses the plustek driver. It turned out that the problem was a dicey usb cable, which kept disconnecting and reconnecting; probably there was a physical break somewhere in the cable. Each time it reconnected, it was given a new bus address and this caused problems with both scanimage and xscanimage, which expect to find the correct address in their default device. It worked with xsane, which starts each scan with a fresh search for available scanners.

I used a different cable and everything worked.

ferrari · 02-26-2019, 01:51 PM

Quote:

Is there a soft way to make scanner usable after boot without needing physical action ? For various reasons, my usb-core driver is in kernel, so can't unload it.

This reads like a power management feature at play...
https://wiki.archlinux.org/index.php...SB_autosuspend
IIRC, some USB scanners have this "power saving" feature built-in.

Another approach may be to reset the USB bus (for the attached device). There are a lot of examples online such as this...
http://billauer.co.il/blog/2013/02/u...ci-uhci-linux/

doublehp · 03-03-2019, 03:04 PM

The email notification was sent to spam folder :/

Quote:

Originally Posted by hazel

I used a different cable and everything worked.

I don't think it's a cable issue, because I only need to cycle the scanner once after boot, then I can use the device for several days.

I don't use power management. I don't use any kind of sleep, only proper poweroff. But, maybe USB chain remains supplied by V standby ...

Code:

  while true ; do lsusb ; date ; sleep 1 ; done &

  for i in ????:??:??.? ; do
    echo -n "$i" > unbind
    sleep 5
    echo -n "$i" > bind
  done

seems to disconnect and reconnect all my devices, not exactly what I Asked for, but, had no downside effect for me. Will try it after next reboot.

ferrari · 03-03-2019, 03:39 PM

Well, yes that will find all devices and reset accordingly. However you're free to identify and reset only the device of interest eg

Code:

echo -n "0000:03:00.0" | tee /sys/bus/pci/drivers/xhci_hcd/unbind
echo -n "0000:03:00.0" | tee /sys/bus/pci/drivers/xhci_hcd/bind

The general idea is to examine /sys/bus/pci/drivers/xhci_hcd (or the appropriate controller directory for your system) to get the pertinent bus address, then unbind and bind as above.

Reference:
https://techadminlab.com/reset-usb-2...-linux-kernel/

ferrari · 03-03-2019, 05:05 PM

Quote:

I don't use power management. I don't use any kind of sleep, only proper poweroff. But, maybe USB chain remains supplied by V standby ...

Just to clarify further here - USB power management is handled at the kernel level, but it can be disabled if necessary. I was also speculating that the USB scanner device may be going into standby mode (and returned to an active state by resetting the USB bus or unplugging and re-plugging physically perhaps).

doublehp · 03-06-2019, 06:15 AM

Quote:

Originally Posted by ferrari

This reads like a power management feature at play...
https://wiki.archlinux.org/index.php...SB_autosuspend
IIRC, some USB scanners have this "power saving" feature built-in.

Another approach may be to reset the USB bus (for the attached device). There are a lot of examples online such as this...
http://billauer.co.il/blog/2013/02/u...ci-uhci-linux/

Works just fine for me:

Code:

$ scanimage -L

No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).
# cd /sys/bus/pci/drivers/?hci_hcd
#   for i in ????:??:??.? ; do
>     echo -n "$i" > unbind
>     sleep 5
>     echo -n "$i" > bind
>   done
$ scanimage -L
device `plustek:libusb:003:004' is a Hewlett-Packard Scanjet 2200c flatbed scanner

Thanks

ferrari · 03-06-2019, 11:24 AM

Good, but at least you now know you can target just the device concerned if required.