Might be a stupid question but

[CBusse]

I have a problem trying to get transfolio to open the usb parallel port I have.

debug log with strace:

execve("./transfolio", ["./transfolio", "-d", "/dev/usb/lp0", "-l", "c:\\"], 0x7fff0c22b600 /* 20 vars */) = 0
brk(NULL)                               = 0x55d235b24000
arch_prctl(0x3001 /* ARCH_??? */, 0x7fffe98819d0) = -1 EINVAL (Invalid argument)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1813d7e000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
newfstatat(3, "", {st_mode=S_IFREG|0644, st_size=22135, ...}, AT_EMPTY_PATH) = 0
mmap(NULL, 22135, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f1813d78000
close(3)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\237\2\0\0\0\0\0"..., 832) = 832
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
pread64(3, "\4\0\0\0 \0\0\0\5\0\0\0GNU\0\2\0\0\300\4\0\0\0\3\0\0\0\0\0\0\0"..., 48, 848) = 48
pread64(3, "\4\0\0\0\24\0\0\0\3\0\0\0GNU\0i8\235HZ\227\223\333\350s\360\352,\223\340."..., 68, 896) = 68
newfstatat(3, "", {st_mode=S_IFREG|0644, st_size=2216304, ...}, AT_EMPTY_PATH) = 0
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
mmap(NULL, 2260560, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1813b50000
mmap(0x7f1813b78000, 1658880, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x28000) = 0x7f1813b78000
mmap(0x7f1813d0d000, 360448, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1bd000) = 0x7f1813d0d000
mmap(0x7f1813d65000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x214000) = 0x7f1813d65000
mmap(0x7f1813d6b000, 52816, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f1813d6b000
close(3)                                = 0
mmap(NULL, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1813b4d000
arch_prctl(ARCH_SET_FS, 0x7f1813b4d740) = 0
set_tid_address(0x7f1813b4da10)         = 1297
set_robust_list(0x7f1813b4da20, 24)     = 0
rseq(0x7f1813b4e0e0, 0x20, 0, 0x53053053) = 0
mprotect(0x7f1813d65000, 16384, PROT_READ) = 0
mprotect(0x55d2358e4000, 4096, PROT_READ) = 0
mprotect(0x7f1813db8000, 8192, PROT_READ) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
munmap(0x7f1813d78000, 22135)           = 0
newfstatat(1, "", {st_mode=S_IFREG|0644, st_size=2440, ...}, AT_EMPTY_PATH) = 0
getrandom("\x29\x2e\x73\x67\x91\x2f\x08\x6a", 8, GRND_NONBLOCK) = 8
brk(NULL)                               = 0x55d235b24000
brk(0x55d235b45000)                     = 0x55d235b45000
openat(AT_FDCWD, "/dev/usb/lp0", O_RDWR) = 3
write(2, "Waiting for /dev/usb/lp0 to beco"..., 48Waiting for /dev/usb/lp0 to become available...^M) = 48
ioctl(3, PPCLAIM, 0)                    = -1 ENOTTY (Inappropriate ioctl for device)
write(2, "PPCLAIM: Inappropriate ioctl for"..., 40PPCLAIM: Inappropriate ioctl for device
) = 40
close(3)                                = 0
write(2, "Try 'fuser -m /dev/usb/lp0' to s"..., 70Try 'fuser -m /dev/usb/lp0' to see if other processes use the device.
) = 70
write(2, "Cannot open parallel port!\n", 27Cannot open parallel port!
) = 27
write(1, "Transfolio 1.0.1 - (c) 2018 by K"..., 44Transfolio 1.0.1 - (c) 2018 by Klaus Peichl
) = 44
exit_group(1)                           = ?
+++ exited with 1 +++

So I got to the point that the adapter is visible in linux

Bus 001 Device 003: ID 1a86:7584 QinHeng Electronics CH340S
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0         8
  idVendor           0x1a86 QinHeng Electronics
  idProduct          0x7584 CH340S
  bcdDevice            2.54
  iManufacturer           0
  iProduct                2 USB2.0-Print
  iSerial                 0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x004e
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         7 Printer
      bInterfaceSubClass      1 Printer
      bInterfaceProtocol      1 Unidirectional
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       1
      bNumEndpoints           2
      bInterfaceClass         7 Printer
      bInterfaceSubClass      1 Printer
      bInterfaceProtocol      2 Bidirectional
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        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     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       2
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass      0
      bInterfaceProtocol    255
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        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     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     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval               1
Device Status:     0x0000
  (Bus Powered)

the exact output while running is

Waiting for /dev/usb/lp0 to become available... PPCLAIM: Inappropriate ioctl for device Try 'fuser -m /dev/usb/lp0' to see if other processes use the device. Cannot open parallel port! Transfolio 1.0.1 - (c) 2018 by Klaus Peichl

fuser -vm /dev/usb/lp0 shows

                     USER        PID ACCESS COMMAND
/dev/usb/lp0:        root     kernel mount /dev
                     root         19 .rc.. kdevtmpfs

what am I missing, why is this a blocking issue?

there should be nothing accessing lp0 at the moment here, no idea why tmpfs is locking this