$ simple-scan -d
[+0,00s] DEBUG: simple-scan.vala:638: Starting Simple Scan 3.32.2.1, PID=21996
[+0,16s] DEBUG: _g_io_module_get_default: Found default implementation dconf (DConfSettingsBackend) for ‘gsettings-backend’
[+0,20s] DEBUG: app-window.vala:1651: Loading state from /home/leo/.cache/simple-scan/state
[+0,20s] DEBUG: app-window.vala:1630: Restoring window to 683x400 pixels
[+0,20s] DEBUG: autosave-manager.vala:64: Loading autosave information
[+0,20s] DEBUG: autosave-manager.vala:259: Waiting to autosave...
[+0,26s] DEBUG: scanner.vala:1485: sane_init () -> SANE_STATUS_GOOD
[+0,26s] DEBUG: scanner.vala:1491: SANE version 1.0.28
[+0,26s] DEBUG: scanner.vala:1552: Requesting redetection of scan devices
[+0,26s] DEBUG: scanner.vala:806: Processing request
[+0,31s] DEBUG: autosave-manager.vala:281: Autosaving book information
[+0,41s] DEBUG: app-window.vala:1712: Saving state to /home/leo/.cache/simple-scan/state
[+4,93s] DEBUG: scanner.vala:341: sane_get_devices () -> SANE_STATUS_GOOD
[+4,93s] DEBUG: scanner.vala:353: Device: name="smfp:usb;04e8;347e;08GMB8GGAE030SV" vendor="Samsung" model="C48x Series sur USB" type="Scanner"
[+4,93s] DEBUG: scanner.vala:353: Device: name="xerox_mfp:libusb:001:004" vendor="Samsung" model="C48x Series" type="multi-function peripheral"
[+4,93s] DEBUG: scanner.vala:353: Device: name="v4l:/dev/video0" vendor="Noname" model="ov9734_azurewave_camera: ov9734" type="virtual device"
[+5,03s] DEBUG: app-window.vala:1712: Saving state to /home/leo/.cache/simple-scan/state
[+32,61s] DEBUG: app-window.vala:1712: Saving state to /home/leo/.cache/simple-scan/state
[+41,82s] DEBUG: app-window.vala:1712: Saving state to /home/leo/.cache/simple-scan/state
[+41,89s] DEBUG: simple-scan.vala:455: Requesting scan at 150 dpi from device 'xerox_mfp:libusb:001:004'
[+41,89s] DEBUG: scanner.vala:1600: Scanner.scan ("xerox_mfp:libusb:001:004", dpi=150, scan_mode=ScanMode.GRAY, depth=2, type=ScanType.SINGLE, paper_width=0, paper_height=0, brightness=-93, contrast=55, delay=10000ms)
[+41,89s] DEBUG: scanner.vala:806: Processing request
[+41,89s] DEBUG: scanner.vala:867: sane_open ("xerox_mfp:libusb:001:004") -> SANE_STATUS_GOOD
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (0)
[+41,89s] DEBUG: scanner.vala:738: Option 0: title='Number of options' type=int size=4 cap=soft-detect
[+41,89s] DEBUG: scanner.vala:741:   Description: Read-only option that specifies how many options a specific devices supports.
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (1)
[+41,89s] DEBUG: scanner.vala:738: Option 1: name='standard' title='Standard' type=group size=4
[+41,89s] DEBUG: scanner.vala:741:   Description: Source, mode and resolution options
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (2)
[+41,89s] DEBUG: scanner.vala:738: Option 2: name='resolution' title='Scan resolution' type=int size=4 unit=dpi values=[75, 100, 150, 200, 300, 600, 1200] cap=soft-select,soft-detect
[+41,89s] DEBUG: scanner.vala:741:   Description: Sets the resolution of the scanned image.
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (3)
[+41,89s] DEBUG: scanner.vala:738: Option 3: name='mode' title='Scan mode' type=string size=9 values=["Lineart", "Halftone", "Gray", "Color"] cap=soft-select,soft-detect
[+41,89s] DEBUG: scanner.vala:741:   Description: Selects the scan mode (e.g., lineart, monochrome, or color).
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (4)
[+41,89s] DEBUG: scanner.vala:738: Option 4: name='highlight' title='Threshold' type=fixed size=4 unit=percent min=30,000000, max=70,000000, quant=655360 cap=soft-select,soft-detect,inactive
[+41,89s] DEBUG: scanner.vala:741:   Description: Select minimum-brightness to get a white point
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (5)
[+41,89s] DEBUG: scanner.vala:738: Option 5: name='source' title='Scan source' type=string size=8 values=["Flatbed", "ADF", "Auto"] cap=soft-select,soft-detect
[+41,89s] DEBUG: scanner.vala:741:   Description: Selects the scan source (such as a document-feeder).
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (6)
[+41,89s] DEBUG: scanner.vala:738: Option 6: name='geometry' title='Geometry' type=group size=4
[+41,89s] DEBUG: scanner.vala:741:   Description: Scan area and media size options
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (7)
[+41,89s] DEBUG: scanner.vala:738: Option 7: name='tl-x' title='Top-left x' type=fixed size=4 unit=mm min=0,000000, max=216,069321, quant=65536 cap=soft-select,soft-detect
[+41,89s] DEBUG: scanner.vala:741:   Description: Top-left x position of scan area.
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (8)
[+41,89s] DEBUG: scanner.vala:738: Option 8: name='tl-y' title='Top-left y' type=fixed size=4 unit=mm min=0,000000, max=297,179993, quant=65536 cap=soft-select,soft-detect
[+41,89s] DEBUG: scanner.vala:741:   Description: Top-left y position of scan area.
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (9)
[+41,89s] DEBUG: scanner.vala:738: Option 9: name='br-x' title='Bottom-right x' type=fixed size=4 unit=mm min=0,000000, max=216,069321, quant=65536 cap=soft-select,soft-detect
[+41,89s] DEBUG: scanner.vala:741:   Description: Bottom-right x position of scan area.
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (10)
[+41,89s] DEBUG: scanner.vala:738: Option 10: name='br-y' title='Bottom-right y' type=fixed size=4 unit=mm min=0,000000, max=297,179993, quant=65536 cap=soft-select,soft-detect
[+41,89s] DEBUG: scanner.vala:741:   Description: Bottom-right y position of scan area.
[+41,89s] DEBUG: scanner.vala:888: sane_get_option_descriptor (11)
[+41,89s] DEBUG: scanner.vala:549: sane_control_option (5, SANE_ACTION_SET_VALUE, "Auto") -> (SANE_STATUS_GOOD, "Auto")
[+41,89s] DEBUG: scanner.vala:549: sane_control_option (3, SANE_ACTION_SET_VALUE, "Gray") -> (SANE_STATUS_GOOD, "Gray")
[+41,89s] DEBUG: scanner.vala:465: sane_control_option (2, SANE_ACTION_SET_VALUE, 150) -> (SANE_STATUS_GOOD, 150)
[+41,89s] DEBUG: scanner.vala:533: sane_control_option (9, SANE_ACTION_SET_VALUE, option.range.max) -> (SANE_STATUS_GOOD)
[+41,89s] DEBUG: scanner.vala:533: sane_control_option (10, SANE_ACTION_SET_VALUE, option.range.max) -> (SANE_STATUS_GOOD)
[+42,23s] DEBUG: app-window.vala:1712: Saving state to /home/leo/.cache/simple-scan/state
[+71,89s] DEBUG: scanner.vala:1241: sane_start (page=0, pass=0) -> SANE_STATUS_IO_ERROR
[+71,89s] WARNING: scanner.vala:1248: Unable to start device: Error during device I/O
[+71,89s] DEBUG: scanner.vala:768: sane_cancel ()
[+71,89s] DEBUG: scanner.vala:771: sane_close ()
[+72,27s] DEBUG: app-window.vala:1712: Saving state to /home/leo/.cache/simple-scan/state