# [SOLVED] USB Scanner not accessible (CanoScan LiDE 20)

## Yminus

This scanner used to work in Gentoo some months ago, but now I cannot access it any more. 

On the first invocation scanimage finds the scanner: 

```
scanimage -L

device `plustek:libusb:001:007' is a Canon CanoScan N670U/N676U/LiDE20 flatbed scanner

```

On every subsequent invocation scanimage fails until I replug the USB cable:

```
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).
```

sane-find-scanner always identifies the scanner:

```
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.

  # Also you need support for SCSI Generic (sg) in your operating system.

  # If using Linux, try "modprobe sg".

found USB scanner (vendor=0x04a9 [Canon], product=0x220d [CanoScan]) at libusb:001:006

could not fetch string descriptor: Overflow

found USB scanner (vendor=0x0bda [Generic], product=0x0129 [USB2.0-CRW]) at libusb:003:003

  # 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.
```

Currently sane-backends-1.0.23-r2 is installed, but I also tried stable 1.0.23 and unstable 1.0.24-r1. All backends are compiled (it is a laptop). I tried with and without avahi and v4l support.

```
eix sane-backends

[I] media-gfx/sane-backends

     Available versions:  1.0.23 (~)1.0.23-r1 (~)1.0.23-r2 ~1.0.24-r1 {avahi doc gphoto2 ipv6 snmp systemd threads usb v4l xinetd SANE_BACKENDS="+abaton +agfafocus +apple +artec +artec_eplus48u +as6e +avision +bh +canon +canon630u +canon_dr +canon_pp +cardscan +coolscan +coolscan2 +coolscan3 +dc210 +dc240 +dc25 +dell1600n_net +dmc +epjitsu +epson +epson2 +fujitsu +genesys +gt68xx +hp +hp3500 +hp3900 +hp4200 +hp5400 +hp5590 +hpljm1005 +hpsj5s +hs2p +ibm +kodak +kodakaio +kvs1025 +kvs20xx kvs40xx +leo +lexmark +ma1509 +magicolor +matsushita +microtek +microtek2 +mustek +mustek_pp +mustek_usb mustek_usb2 +nec +net +niash +p5 +pie +pixma +plustek +plustek_pp -pnm +qcam +ricoh +rts8891 +s9036 +sceptre +sharp +sm3600 +sm3840 +snapscan +sp15c +st400 +stv680 +tamarack +teco1 +teco2 +teco3 +test +u12 +umax +umax1220u +umax_pp +xerox_mfp"}

     Installed versions:  1.0.23-r2(00:04:48 10.12.2013)(avahi gphoto2 ipv6 snmp threads usb v4l xinetd -doc SANE_BACKENDS="abaton agfafocus apple artec artec_eplus48u as6e avision bh canon canon630u canon_dr canon_pp cardscan coolscan coolscan2 coolscan3 dc210 dc240 dc25 dell1600n_net dmc epjitsu epson epson2 fujitsu genesys gt68xx hp hp3500 hp3900 hp4200 hp5400 hp5590 hpljm1005 hpsj5s hs2p ibm kodak kodakaio kvs1025 kvs20xx kvs40xx leo lexmark ma1509 magicolor matsushita microtek microtek2 mustek mustek_pp mustek_usb mustek_usb2 nec net niash p5 pie pixma plustek plustek_pp pnm qcam ricoh rts8891 s9036 sceptre sharp sm3600 sm3840 snapscan sp15c st400 stv680 tamarack teco1 teco2 teco3 test u12 umax umax1220u umax_pp xerox_mfp")

     Homepage:            http://www.sane-project.org/

     Description:         Scanner Access Now Easy - Backends
```

'plustek' is *not* commented out in /etc/sane.d/dll.conf.

My current kernel is 3.11.8-gentoo but I also tried 3.8.13.

dmesg shows: 

```
[27466.228938] usb 1-2: new full-speed USB device number 8 using xhci_hcd

[27466.241050] usb 1-2: New USB device found, idVendor=04a9, idProduct=220d

[27466.241054] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0

[27466.241056] usb 1-2: Product: CanoScan

[27466.241058] usb 1-2: Manufacturer: Canon
```

lsusb:

```
Bus 001 Device 009: ID 04a9:220d Canon, Inc. CanoScan N670U/N676U/LiDE 20
```

When I give the device name it also fails:

```
 scanimage -d plustek:libusb:001:010

scanimage: open of device plustek:libusb:001:010 failed: Error during device I/O
```

Note that the USB device number is incremented each time I replug the device.

Since I have USB3 ports I tried with all ports of my laptop. And I tried everything as root user (and most as regular user, too).

Other USB devices are working, e.g. at the moment I am typing on an USB keyboard.

Can someone please give me an idea what may be wrong or how I could isolate this problem?Last edited by Yminus on Fri May 27, 2016 10:04 pm; edited 1 time in total

----------

## Yminus

I have more info to add:

The scanner works in Bodhi Linux 2.4. (based on Ubuntu 12.04, Kernel 3.7.0-7-generic) on an old Asus Eee PC 4G (no USB 3.0).

I tried to remove the xhci_hcd module (USB 3.0) and load ehci_hcd instead (USB 2.0), but this disables all my USB ports (dmesg shows nothing when USB devices are plugged in).

I tried scanimage -L in debug mode (omitted lines are marked with [...]):

```
# export SANE_DEBUG_PLUSTEK=128

# export SANE_DEBUG_DLL=128

# export SANE_DEBUG_USB=128

# scanimage -L

[sanei_debug] Setting debug level of dll to 128.

[dll] sane_init: SANE dll backend version 1.0.13 from sane-backends 1.0.23

[dll] sane_init/read_dlld: attempting to open directory `./dll.d'

[dll] sane_init/read_dlld: attempting to open directory `/etc/sane.d/dll.d'

[dll] sane_init/read_dlld: using config directory `/etc/sane.d/dll.d'

[dll] sane_init/read_dlld: done.

[dll] sane_init/read_config: reading dll.conf

[dll] add_backend: adding backend `net'

[dll] add_backend: adding backend `abaton'

[dll] add_backend: adding backend `agfafocus'

[... a lot of add_backend lines omitted ...]

[dll] add_backend: adding backend `plustek'

[dll] add_backend: adding backend `plustek_pp'

[... a lot of add_backend lines omitted ...]

[dll] sane_get_devices

[dll] load: searching backend `epkowa' in `/usr/lib64/sane'

[dll] load: trying to load `/usr/lib64/sane/libsane-epkowa.so.1'

[dll] load: couldn't open `/usr/lib64/sane/libsane-epkowa.so.1' (No such file or directory)

[dll] load: couldn't find backend `epkowa' (No such file or directory)

[... a lot of failing "load:" lines omitted ...]

[dll] load: searching backend `plustek' in `/usr/lib64/sane'

[dll] load: trying to load `/usr/lib64/sane/libsane-plustek.so.1'

[dll] load: dlopen()ing `/usr/lib64/sane/libsane-plustek.so.1'

[dll] init: initializing backend `plustek'

[sanei_debug] Setting debug level of plustek to 128.

[plustek] Plustek backend V0.52-10, part of sane-backends 1.0.23

[plustek] Retrieving all supported and conntected devices

[plustek] Checking for 0x07b3-0x0010

[... a lot of "checking for" lines omitted ...]

[plustek] Checking for 0x04a9-0x220d

[... a lot of "checking for" lines omitted ...]

[plustek] Available and supported devices:

[plustek] Device: >libusb:001:005< - 0x04a9x0x220d

[plustek] ># Plustek-SANE Backend configuration file<

[plustek] ># For use with LM9831/2/3 based USB scanners<

[plustek] >#<

[plustek] ><

[plustek] ># each device needs at least two lines:<

[plustek] ># - [usb] vendor-ID and product-ID<

[plustek] ># - device devicename<

[plustek] ># i.e. for Plustek (0x07B3) UT12/16/24 (0x0017)<

[plustek] ># [usb] 0x07B3 0x0017<

[plustek] ># device /dev/usbscanner<

[plustek] ># or<

[plustek] ># device libusb:bbb:ddd<

[plustek] ># where bbb is the busnumber and ddd the device number<

[plustek] ># make sure that your user has access to /proc/bus/usb/bbb/ddd<

[plustek] >#<

[plustek] ># additionally you can specify some options<

[plustek] ># warmup, lOffOnEnd, lampOff<

[plustek] >#<

[plustek] ># For autodetection use<

[plustek] ># [usb]<

[plustek] ># device /dev/usbscanner<

[plustek] >#<

[plustek] ># or simply<

[plustek] ># [usb]<

[plustek] >#<

[plustek] ># or if you want a specific device but you have no idea about the<

[plustek] ># device node or you use libusb, simply set vendor- and product-ID<

[plustek] ># [usb] 0x07B3 0x0017<

[plustek] ># device auto<

[plustek] >#<

[plustek] ># NOTE: autodetection is safe, as it uses the info it got<

[plustek] >#       from the USB subsystem. If you're not using the<

[plustek] >#       autodetection, you MUST have attached that device<

[plustek] >#       at your USB-port, that you have specified...<

[plustek] >#<

[plustek] ><

[plustek] >[usb]<

[plustek] next device uses autodetection

[plustek] ... next device

[plustek] ><

[plustek] >#<

[plustek] ># options for the previous USB entry<

[plustek] >#<

[plustek] ># switch lamp off after xxx secs, 0 disables the feature<

[plustek] ># (can also be set via frontend)<

[plustek] >option lampOff 300<

[plustek] Decoding option >lampOff<

[plustek] ><

[plustek] ># warmup period in seconds, 0 means no warmup, -1 means auto-warmup<

[plustek] ># (can also be set via frontend)<

[plustek] >option warmup -1<

[plustek] Decoding option >warmup<

[plustek] ><

[plustek] ># 0 means leave lamp-status untouched, not 0 means switch off<

[plustek] ># on sane_close<

[plustek] ># (can also be set via frontend)<

[plustek] >option lOffOnEnd 1<

[plustek] Decoding option >lOffOnEnd<

[plustek] ><

[plustek] >#<

[plustek] ># options to tweak the image start-position<

[plustek] ># (WARNING: there's no internal range check!!!)<

[plustek] >#<

[plustek] ># for the normal scan area<

[plustek] >#<

[plustek] >option posOffX 0<

[plustek] Decoding option >posOffX<

[plustek] >option posOffY 0<

[plustek] Decoding option >posOffY<

[plustek] ><

[plustek] ># for transparencies<

[plustek] >option tpaOffX 0<

[plustek] Decoding option >tpaOffX<

[plustek] >option tpaOffY 0<

[plustek] Decoding option >tpaOffY<

[plustek] ><

[plustek] ># for negatives<

[plustek] >option negOffX 0<

[plustek] Decoding option >negOffX<

[plustek] >option negOffY 0<

[plustek] Decoding option >negOffY<

[plustek] ><

[plustek] >#<

[plustek] ># for setting the calibration strip position<

[plustek] ># (WARNING: there's no internal range check!!!)<

[plustek] ># -1 means use built in<

[plustek] ># (can also be set via frontend)<

[plustek] >option posShadingY -1<

[plustek] Decoding option >posShadingY<

[plustek] >option tpaShadingY -1<

[plustek] Decoding option >tpaShadingY<

[plustek] >option negShadingY -1<

[plustek] Decoding option >negShadingY<

[plustek] ><

[plustek] >#<

[plustek] ># to invert the negatives, 0 disables the feature<

[plustek] >#<

[plustek] >option invertNegatives 0<

[plustek] Decoding option >invertNegatives<

[plustek] ><

[plustek] >#<

[plustek] ># to disable the internal sensor speedup function,<

[plustek] ># 1 disables the feature<

[plustek] >#<

[plustek] >option disableSpeedup 0<

[plustek] Decoding option >disableSpeedup<

[plustek] ><

[plustek] >#<

[plustek] ># to save/restore coarse calibration data<

[plustek] ># (can also be set via frontend)<

[plustek] >option cacheCalData 0<

[plustek] Decoding option >cacheCalData<

[plustek] ><

[plustek] >#<

[plustek] ># use alternate calibration routines<

[plustek] >#<

[plustek] >option altCalibration 0<

[plustek] Decoding option >altCalibration<

[plustek] ><

[plustek] >#<

[plustek] ># for skipping whole calibration step<

[plustek] >#<

[plustek] >option skipCalibration 0<

[plustek] Decoding option >skipCalibration<

[plustek] ><

[plustek] >#<

[plustek] ># for skipping entire fine calibration step<

[plustek] ># coarse calibration is done<

[plustek] >#<

[plustek] >option skipFine 0<

[plustek] Decoding option >skipFine<

[plustek] ><

[plustek] >#<

[plustek] ># discard the result of the fine white calibration<

[plustek] >#<

[plustek] >option skipFineWhite 0<

[plustek] Decoding option >skipFineWhite<

[plustek] ><

[plustek] >#<

[plustek] ># some scanners have a dark calibration strip, in<

[plustek] ># general this one should be used for calibration.<

[plustek] ># As this could cause some trouble, this option<

[plustek] ># overrides that and the dark calibration will be<

[plustek] ># done by switching the lamp off<

[plustek] >#<

[plustek] >option skipDarkStrip 0<

[plustek] Decoding option >skipDarkStrip<

[plustek] ><

[plustek] ># for replacing the gain values found during coarse<

[plustek] ># calibration<

[plustek] ># (can also be set via frontend)<

[plustek] >option red_gain   -1<

[plustek] Decoding option >red_gain<

[plustek] >option green_gain -1<

[plustek] Decoding option >green_gain<

[plustek] >option blue_gain  -1<

[plustek] Decoding option >blue_gain<

[plustek] ><

[plustek] ># for replacing the offset values found during coarse<

[plustek] ># calibration<

[plustek] ># (can also be set via frontend)<

[plustek] >option red_offset   -1<

[plustek] Decoding option >red_offset<

[plustek] >option green_offset -1<

[plustek] Decoding option >green_offset<

[plustek] >option blue_offset  -1<

[plustek] Decoding option >blue_offset<

[plustek] ><

[plustek] >#<

[plustek] ># for replacing the default lampoff settings, this<

[plustek] ># works only for CIS devices like CanoScan LiDE20<

[plustek] ># (can also be set via frontend)<

[plustek] >option red_lampoff   -1<

[plustek] Decoding option >red_lampoff<

[plustek] >option green_lampoff -1<

[plustek] Decoding option >green_lampoff<

[plustek] >option blue_lampoff  -1<

[plustek] Decoding option >blue_lampoff<

[plustek] ><

[plustek] >#<

[plustek] ># for adjusting the default gamma values<

[plustek] ># (can also be set via frontend)<

[plustek] >option redGamma         1.0<

[plustek] Decoding option >redGamma<

[plustek] >option greenGamma       1.0<

[plustek] Decoding option >greenGamma<

[plustek] >option blueGamma        1.0<

[plustek] Decoding option >blueGamma<

[plustek] >option grayGamma        1.0<

[plustek] Decoding option >grayGamma<

[plustek] ><

[plustek] >#<

[plustek] ># to enable TPA (EPSON or UMAX, if autodetection fails)<

[plustek] ># 0 means default behaviour as specified in the internal tables<

[plustek] ># 1 means enable (needed for UMAX 3450)<

[plustek] >option enableTPA 0<

[plustek] Decoding option >enableTPA<

[plustek] ><

[plustek] >#<

[plustek] ># model override functionality, currently only available for<

[plustek] ># Mustek devices, using NSCs' vendor ID: 0x0400 and<

[plustek] ># also their product ID: 0x1000 (LM9831) 0x1001 (LM9832)<

[plustek] >#<

[plustek] ># mov/PID    |    0x1000   |   0x1001<

[plustek] ># ---------------------------------------<

[plustek] ># 0 (default)| BearPaw1200 | BearPaw 2400<

[plustek] ># 1          |   ignored   | BearPaw 1200<

[plustek] >#<

[plustek] >option mov 0<

[plustek] Decoding option >mov<

[plustek] ><

[plustek] >#<

[plustek] ># and of course the device-name<

[plustek] >#<

[plustek] ># device /dev/usbscanner<

[plustek] >device auto<

[plustek] Decoding device name >auto<

[plustek] ><

[plustek] >#<

[plustek] ># to define a new device, start with a new section:<

[plustek] ># [usb]<

[plustek] >#<

[plustek] attach (auto, 0x7fffb3626c70, (nil))

[plustek] Device configuration:

[plustek] device name  : >auto<

[plustek] USB-ID       : ><

[plustek] model ovr.   : 0

[plustek] warmup       : -1s

[plustek] lampOff      : 300

[plustek] lampOffOnEnd : yes

[plustek] cacheCalData : no

[plustek] altCalibrate : no

[plustek] skipCalibr.  : no

[plustek] skipFine     : no

[plustek] skipFineWhite: no

[plustek] skipDarkStrip: no

[plustek] incDarkTarget: yes

[plustek] invertNegs.  : no

[plustek] dis.Speedup  : no

[plustek] pos_x        : 0

[plustek] pos_y        : 0

[plustek] pos_shading_y: -1

[plustek] neg_x        : 0

[plustek] neg_y        : 0

[plustek] neg_shading_y: -1

[plustek] tpa_x        : 0

[plustek] tpa_y        : 0

[plustek] tpa_shading_y: -1

[plustek] red gain     : -1

[plustek] green gain   : -1

[plustek] blue gain    : -1

[plustek] red offset   : -1

[plustek] green offset : -1

[plustek] blue offset  : -1

[plustek] red lampoff  : -1

[plustek] green lampoff: -1

[plustek] blue lampoff : -1

[plustek] red Gamma    : 1.00

[plustek] green Gamma  : 1.00

[plustek] blue Gamma   : 1.00

[plustek] gray Gamma   : 1.00

[plustek] ---------------------

[plustek] usbDev_open(auto,) - 0x1605cd0

[plustek] Vendor ID=0x04A9, Product ID=0x220D

[plustek] usbio_DetectLM983x

[... HERE COMES THE ERROR:]

[plustek]  * could not read version register!

[plustek] open failed: -1

[dll] init: backend `plustek' is version 1.0.0

[plustek] sane_get_devices (0x7fffb3627de8, 0)

[dll] load: searching backend `pixma' in `/usr/lib64/sane'

[dll] load: trying to load `/usr/lib64/sane/libsane-pixma.so.1'

[dll] load: dlopen()ing `/usr/lib64/sane/libsane-pixma.so.1'

[... a lot of failing "init:" lines omitted ...]

[dll] sane_get_devices: found 0 devices

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).

[dll] sane_exit: exiting

[dll] sane_exit: calling backend `hpaio's exit function

[... a lot of "calling backend ... exit function" lines omitted ...]

[dll] sane_exit: calling backend `plustek's exit function

[plustek] sane_exit

[... a lot of "calling backend ... exit function" lines omitted ...]

dll] sane_exit: finished
```

After searching for the error in the www I found out, that I am not alone:

sane plustek backend not working on USB 3 root hub

----------

## Yminus

I reported this bug:

plustek backend not working on USB 3.0

----------

## DeIM

Hi, I'm facing the same problem.   :Sad: 

```
usb 3-12: new full-speed USB device number 7 using xhci_hcd

usb 3-12: New USB device found, idVendor=04a9, idProduct=2220

usb 3-12: New USB device strings: Mfr=1, Product=2, SerialNumber=0

usb 3-12: Product: CanoScan

usb 3-12: Manufacturer: Canon

```

```
scanimage -L

device `plustek:libusb:003:008' is a Canon CanoScan LiDE25 flatbed scanner
```

```
lsusb

Bus 002 Device 002: ID 8087:8001 Intel Corp. 

Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Bus 001 Device 002: ID 8087:8009 Intel Corp. 

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub

Bus 003 Device 008: ID 04a9:2220 Canon, Inc. CanoScan LIDE 25

```

I've USB 3.0 and USB 2.0 but both seems to be managed by xhci_hcd.

Is there any solution yet?

Could be xhci_hcd forced to ehci_hcd for some device?

Thank for any help.

----------

## albright

 *Quote:*   

> Could be xhci_hcd forced to ehci_hcd for some device? 

 

I will resurrect this thread since I've got the same problem.

Has there been any advance on this?

Is it indeed possible to force the scanner to use the ehci module (via a usb 2.0

port)?

(I have an intel nuc and connected the motherboard's usb 2.0 header to some

ports; the scanner is seen in lsusb

```
Bus 001 Device 013: ID 04a9:2220 Canon, Inc. CanoScan LIDE 25
```

but the symptoms as in the OP remain   :Crying or Very sad: 

----------

## albright

Here's a slightly convoluted work around that works for me

1. Install ubuntu as vmware virtual machine

2. plug in scanner to usb 2.0 port while VM is active window (so VM grabs the usb port)

3. scanimage -L finds the scanner no problem in ubuntu

4. scan away!

(VMs are great)

----------

## DeIM

Great you've found this workaround.

I've disabled XHCI in BIOS to get scanner to work. I know it isn't the best solution  :Sad: 

Gerhard Jaeger in link above (https://alioth.debian.org/tracker/index.php?func=detail&aid=314545&group_id=30186&atid=410366) wrote it's already fixed in kernel but I didn't notice any change even on newest stable kernel (gentoo-sources).

----------

## Yminus

My workaround was to attach the scanner to my NAS which only had usb 2.0 ports and then share it on the network. On my NAS I only had to add the file /etc/sane.d/saned.conf with my IP subnet 

```
192.168.1.0/24
```

On my laptop in /etc/sane.d/net.conf I added the IP (or URL) of my NAS in a single line, e.g. 

```
192.168.1.4
```

But this is only for the record.

Meanwhile bug [#314545] has been fixed upstream. Just add 

```
~media-gfx/sane-backends-1.0.25
```

 to your /etc/portage/package.keywords and update media-gfx/sane-backends.

----------

## DeIM

Yes, it works finally. Thanks for notice  :Very Happy: 

----------

## yayo

Same problem here. Canoscan Lide20. Not solved.

kernel 4.4.21.

I updated to sane-backends 1.0.25 via package.keywords as suggested, but it's still not working.

xsane takes around 1 minute to find the devices.

Once I get the list and select the Lide 20, I cannot get it to works (device I/O error).

If I close and restart xsane, it no longer sees the scanner and fall automatically to the webcam device. I must unplug and replug it to make it available again.

Suggestions? Did I miss something? : /

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## yayo

Bump!

sorry for reopening this, but I'm having some issues with my hardware/software (cd, webcam, scanner...) and I find it very frustrating. I'm almost pretty sure this scanner works perfectly even if it's old, because it's been used only a few times and stored with care.

I don't need it right now, but I know for experience that it may happens anytime and I'd like to understand now if I can rely on it in case of need. : /

This one is a laptop with 3 usb ports, 2 are usb3 and the last is usb2.

When I plug the cable the system seems to recognize it, dmesg shows this:

```
[ 3341.639793] usb 2-2: new full-speed USB device number 13 using xhci_hcd

[ 3341.805357] usb 2-2: New USB device found, idVendor=04a9, idProduct=220d

[ 3341.805362] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0

[ 3341.805364] usb 2-2: Product: CanoScan

[ 3341.805366] usb 2-2: Manufacturer: Canon

```

then I do scanimage -L and after a loong time (around 1 minute) I get this output:

```
device `v4l:/dev/video0' is a Noname USB2.0 VGA UVC WebCam virtual device

device `plustek:libusb:002:013' is a Canon CanoScan N670U/N676U/LiDE20 flatbed scanner

```

at the same time I get a now dmesg line written in bold:

```
[ 3479.397982] xhci_hcd 0000:00:14.0: URB transfer length is wrong, xHC issue? req. len = 0, act. len = 4294967288

```

and subsequent scanimage -L call gives istantly the 1st device only (the webcam):

```
device `v4l:/dev/video0' is a Noname USB2.0 VGA UVC WebCam virtual device

```

and scanner is gone.

If I start xsane right after plugging the cable I get the same long waiting, then I select the device, then I can do nothing else (any attempt at using the scanner gives me I/O error).

I have latest sane backends version installed.

Both usb2 and usb3 port show the same behavior.

wtf?

Is there something else I can try before to give up?

(maybe reopening a new thread since this one is marked as solved, while in fact it's not for me...? ._. )

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## yayo

Ok, seems to be solved. I spent 2 days trying almost anything, but in the end I won. ^^

The problem was apparently in a damaged connection cable. A new one fixed the trouble. To be honest I didn't remember the scanner beging so slow in movement, but it's perhaps something related to the plustek backend setting.

Still I don't get what's wrong with the usb3 dmesg error. Seems to be related to the usb3 bios setting, but apparently that cannot be fixed, because turn such option off would mean to turn off usb3 and get usb2 only (which is a big waste!). Nevermind. If it works I'm ok for now.

Now gonna fix the webcam. I'll probably open a thread on purpose soon.

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