/dev/lpt0 - always busy, except when acpi is disabled

From: Andrew Konstantinov (andrei_at_andruxa.sytes.net)
Date: 08/28/03

  • Next message: Kenneth D. Merry: "Re: bcm4400 driver and Dell 8500" 
    Date: Wed, 27 Aug 2003 17:00:16 -0700
To: hackers@freebsd.org

    Hello,

    I am running: FreeBSD xxxxxxx.xxxxx.xxx 5.1-CURRENT FreeBSD 5.1-CURRENT #0:
    Tue Aug 26 21:02:35 PDT 2003
    root@xxxxxxx.xxxxx.xxx:/usr/obj/usr/src/sys/CUSTOM i386

    I have a problem accessing the printer connected to the box via parallel
    port. Whenever I try to send something to /dev/lpt0, it always responds with
    'device busy' error message, while that device is not being used by any
    other program. This behavior started once I upgraded to 5.1-release and
    continues through 'current.' When I was using 5.0-release, the system worked
    fine and I never had this problem, but once I upgraded, this mystery started
    to happen.

    Here is some background info.

    My kernel configuration file contains the following devices:
    device ppc
    device ppbus # Parallel port bus (required)
    device lpt # Printer
    device ppi # Parallel port interface device

    PPC hints in the /boot/device.hints file are:
    hint.ppc.0.at="isa"
    hint.ppc.0.irq="7"

    As you can see, irq number is specified, so the system is supposed to
    communicate with the printer in interrupt-driven mode. But, for some
    misterious reason that doesn't happen. Here is the part of my dmesg output
    related to pp* and lpt:

    ppc0 port 0-0x7 on acpi0
    ppc0: Generic chipset (ECP/PS2/NIBBLE) in COMPATIBLE mode
    ppbus0: <Parallel port bus> on ppc0
    lpt0: <Printer> on ppbus0
    lpt0: Polled port
    ppi0: <Parallel I/O> on ppbus0

    As you can see, the communication is carried out in polled mode. I am not
    sure why...?

    I was going back and forth trying to make the printer work and found a
    'solution' for that problem. The 'solution' is to disable acpi.
    hint.acpi.0.disabled="1" - works like a charm. After disabling acpi I get
    the ability to use my printer and the following dmesg output:

    ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0
    ppc0: Generic chipset (NIBBLE-only) in COMPATIBLE mode
    ppbus0: <Parallel port bus> on ppc0
    ppbus0: IEEE1284 device found /NIBBLE
    Probing for PnP devices on ppbus0:
    ppbus0: <EPSON Stylus COLOR 777> PRINTER ESCPL2,BDC,D4
    lpt0: <Printer> on ppbus0
    lpt0: Interrupt-driven port
    ppi0: <Parallel I/O> on ppbus0

    As I already mentioned, this never happened when my box was running
    5.0-release, but started to happen right after the moment when I upgraded to
    5.1-release, and continues to happen on 5.1-current.

    I am wondering if this is a bug in the source code and can only be fixed
    with a patch, or there is a work around through acpi configuration? ACPI
    manual page says that one can disable parts of acpi through
    'debug.acpi.disable' kernel environment variable. In that case, what is the
    minimal set of sub-devices that I would temporarly have to disable to
    resolve this problem?
    Perhaps I got right in the middle of ongoing work with acpi?

    Any hints, pointers or links will be greatly appreciated!
    Thanks in advance.

    Andrew

  • Next message: Kenneth D. Merry: "Re: bcm4400 driver and Dell 8500"

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