Unfunctional scanner in Ubuntu 20.10
As written to the sane-devel list, since upgrading to Ubuntu 20.10 yesterday my scanner refuses to scan. I'll write down what I have tried so far:
```
$ 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).
```
Which is the base of the problem and this issue.
```
$ 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=0x04a9 [Canon], product=0x220d [CanoScan], chip=LM9832/3) at libusb:001:013
# Your USB scanner was (probably) detected. It may or may not be supported by
# SANE. Try scanimage -L and read the backend's manpage.
```
^^ So sane-find-scanner finds my scanner correctly as a libusb device
```
$ lsusb -v
Bus 001 Device 005: ID 04a9:220d Canon, Inc. CanoScan N670U/N676U/LiDE 20
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 255 Vendor Specific Class
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x04a9 Canon, Inc.
idProduct 0x220d CanoScan N670U/N676U/LiDE 20
bcdDevice 1.00
iManufacturer 64 Canon
iProduct 77 CanoScan
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x0027
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 3
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 0
bInterfaceProtocol 255
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0001 1x 1 bytes
bInterval 16
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
can't get debug descriptor: Resource temporarily unavailable
Device Status: 0x0000
(Bus Powered)
```
```
$ dmesg -w
[ 1027.863405] usb 1-1: new full-speed USB device number 6 using xhci_hcd
[ 1028.023470] usb 1-1: New USB device found, idVendor=04a9, idProduct=220d, bcdDevice= 1.00
[ 1028.023475] usb 1-1: New USB device strings: Mfr=64, Product=77, SerialNumber=0
[ 1028.023479] usb 1-1: Product: CanoScan
[ 1028.023481] usb 1-1: Manufacturer: Canon
```
```# scanimage -L``` (as root) no success
libsane in Ubuntu 20.10 is at 1.0.31-2
I'm running a self-compiled kernel 5.8.14, but the distro kernel 5.8.0 doesn't work as well.
I have succesfully scanned a week ago on this same hardware using Ubuntu 20.04, kernel 5.8.12
plustek is mentioned uncommented in /etc/sane.d/dll.conf
I'm a developer, so willing (and able) to compile test code to debug where in the chain (libusb?) things go wrong.
issue