Re^2: use Perl With usblp Parallel Adapter

Thanks. I modified the Device::ParallelPort::drv::linux module, and in the init() function I added the code:

$this->{DATA}{DEVICE} = "lp0";
[download]

before the "linux_opendev" call, but the result is the same: I can't set (and probably get) the data bits (this is the result of your script almut):

Data port:    ff  11111111
Control port: ff  11111111
Status port:  ff  11111111
set  bit 0 to 0
read bit 0:   1
set  bit 0 to 1
read bit 0:   1
set  bit 0 to 0
read bit 0:   1
set  bit 2 to 1
read bit 2:   1
Bit 0: 1
Data port:    ff  11111111
set data      'a' (0x61 01100001)
Data port:    ff  11111111
set control    4  (bit 2)
Control port: ff  11111111
Status port:  ff  11111111
[download]

I tried to change "lp0" in this->{DATA}{DEVICE} to "/dev/usb/lp0", but nothing changed... I think that my usb adapter is not so compatible with Linux or maybe it's not a really usb to parallel port adapter...

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Re^3: use Perl With usblp Parallel Adapter by almut (Canon) on Oct 04, 2009 at 12:31 UTC
I tried to change "lp0" in this->{DATA}{DEVICE} to "/dev/usb/lp0", but nothing changed... As I said, that value is only ever being used in an error message. The purpose behind setting it was just to silence the warning... I think that my usb adapter is not so compatible with Linux or maybe it's not a really usb to parallel port adapter... Either that, or it isn't mapped to the I/O address 0x378 (which is hardcoded in Device::ParallelPort::drv::linux::linux_opendev() ). The code in question is: `... base = 0x378; if (ioperm(base, LPSIZE, 1) < 0) { fprintf(stderr, "%s: ioperm:%s ", devname, strerror(errno) +); RETVAL = -1; } else { RETVAL = base; }` [download] `ioperm(2)` can only fail with `EINVAL Invalid address(-range). EPERM The calling process has insufficient privilege. ENOMEM Out of memory. EIO This call is not supported (on PowerPC).` [download] In particular, no checks are being made that the address actually maps to the intended hardware device. You might want to check your `dmesg` output — mine, for example, says: `[ 61.718702] parport_pc 00:0b: reported by Plug and Play ACPI [ 61.718797] parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE] [ 63.870838] lp0: using parport0 (interrupt-driven).` [download]	[reply] [d/l] [select]

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Re^3: use Perl With usblp Parallel Adapter
by almut (Canon) on Oct 04, 2009 at 12:31 UTC

I tried to change "lp0" in this->{DATA}{DEVICE} to "/dev/usb/lp0", but nothing changed...

As I said, that value is only ever being used in an error message. The purpose behind setting it was just to silence the warning...

I think that my usb adapter is not so compatible with Linux or maybe it's not a really usb to parallel port adapter...

Either that, or it isn't mapped to the I/O address 0x378 (which is hardcoded in Device::ParallelPort::drv::linux::linux_opendev() ). The code in question is:

    ...
    base = 0x378;
    if (ioperm(base, LPSIZE, 1) < 0) {
            fprintf(stderr, "%s: ioperm:%s ", devname, strerror(errno)
+);
            RETVAL = -1;
    } else {
            RETVAL = base;
    }
[download]

ioperm(2) can only fail with

    EINVAL Invalid address(-range).
    EPERM  The calling process has insufficient privilege.
    ENOMEM Out of memory.
    EIO    This call is not supported (on PowerPC).
[download]

In particular, no checks are being made that the address actually maps to the intended hardware device.

You might want to check your dmesg output — mine, for example, says:

[   61.718702] parport_pc 00:0b: reported by Plug and Play ACPI
[   61.718797] parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE]
[   63.870838] lp0: using parport0 (interrupt-driven).
[download]

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