IRQ on PCMCIA Modem - Portable

This is a discussion on IRQ on PCMCIA Modem - Portable ; Hi everyone, I'm trying to set up a PCMCIA modem ("Mercury 56k Fax Modem Card", FCC ID 5HRTAI-31904-M5-E) to work on a Linux notebook with a customised kernel 2.4.21. In principle, the Modem does work as /dev/ttyS1, but it's extremely ...

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Thread: IRQ on PCMCIA Modem

  1. IRQ on PCMCIA Modem

    Hi everyone,

    I'm trying to set up a PCMCIA modem ("Mercury 56k Fax Modem Card", FCC
    ID 5HRTAI-31904-M5-E) to work on a Linux notebook with a customised
    kernel 2.4.21. In principle, the Modem does work as /dev/ttyS1, but
    it's extremely slow.auf einem System mit einem angepassten

    Based on what I read in the PCMCIA Howto, the problem is most likely an
    interrupt conflict:

    | If the modem seems to work only very, very slowly, this is an almost
    | certain indicator of an interrupt conflict.

    However, at the moment, the modem seems not to use and interrupt but is
    "working" in polled mode (IRQ 0):

    [root@eclipse pcmcia] setserial /dev/ttyS1
    /dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 0

    This is most likely the main reason of my problem. From the PCMCIA-Howto:

    | ... try using setserial to change the irq to 0, and see if the modem
    | works. This causes the serial driver to use a slower polled mode
    | instead of using interrupts.

    I think I should also mention the output of cardctl, where no IRQ is
    shown for the modem in socket 1:

    [root@eclipse pcmcia] cardctl config
    Socket 0:
    Vcc 3.3V Vpp1 3.3V Vpp2 3.3V
    interface type is "cardbus"
    irq 10 [exclusive] [level]
    function 0:
    Socket 1:
    Vcc 5.0V Vpp1 0.0V Vpp2 0.0V
    interface type is "memory and I/O"
    speaker output is enabled
    function 0:
    config base 0x0100
    option 0x61 status 0x08 ext 0x00
    io 0x02f8-0x02ff [8bit]

    So I have two questions:

    - How can I find a free IRQ? Is this just by looking for missing entries
    in /proc/interrupts? What irritated me a bit was that /dev/ttyS0 is on
    IRQ 4 (setserial) but not shown upon cat /proc/interrupts.

    - On a RedHat system, how do I assign the free IRQ I found to the modem
    correctly? Trying to change SERIAL_OPTS in /etc/pcmcia/serial.opts was
    not very successful (I could get the modem to use anIRQ but it did not
    work anymore).

    Thanks in advance,

    Guenter

  2. Re: IRQ on PCMCIA Modem

    In comp.os.linux.portable Guenter Resch wrote:

    > [root@eclipse pcmcia] setserial /dev/ttyS1
    > /dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 0


    My first guess is that you've configured your kernel with CONFIG_ISA
    disabled. Enable that and try again.

    -- Dave

  3. Re: IRQ on PCMCIA Modem

    dhinds@sonic.net wrote ...
    > In comp.os.linux.portable Guenter Resch wrote:
    >
    >> [root@eclipse pcmcia] setserial /dev/ttyS1
    >> /dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 0

    >
    > My first guess is that you've configured your kernel with CONFIG_ISA
    > disabled. Enable that and try again.


    Unfortunately, enabling CONFIG_ISA did not change the situation.

    When start with empty SERIAL_OPTS in /etc/pcmcia/serial.opts, the
    modem is still running in polled mode (IRQ 0), when I force it to use
    either IRQ 3 or 5 (SERIAL_OPTS="irq 5"; only one serial and parallel
    port present on the system, so these two should be free), I get an
    output like this:

    [root@eclipse root] setserial /dev/ttyS1
    /dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 5

    [root@eclipse root] cardctl config
    Socket 0:
    Vcc 3.3V Vpp1 3.3V Vpp2 3.3V
    interface type is "cardbus"
    irq 10 [exclusive] [level]
    function 0:
    Socket 1:
    Vcc 5.0V Vpp1 0.0V Vpp2 0.0V
    interface type is "memory and I/O"
    speaker output is enabled
    function 0:
    config base 0x0100
    option 0x61 status 0x08 ext 0x00
    io 0x02f8-0x02ff [8bit]

    However, wvdial tells me that the modem does not respond when I'm trying
    to use /dev/ttyS1 :-(

    Any more suggestions what to try?

    Guenter

  4. Re: IRQ on PCMCIA Modem

    dhinds@sonic.net wrote:
    > In comp.os.linux.portable Guenter Resch wrote:
    >
    >
    >> [root@eclipse pcmcia] setserial /dev/ttyS1
    >> /dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 0

    >
    >
    > My first guess is that you've configured your kernel with CONFIG_ISA
    > disabled. Enable that and try again.


    Many thanks, Dave

    You just helped cure my problems with a PCMCIA NIC under kernel 2.4.22

    Who would'a thought that a laptop with /just/ PCMCIA slots would need /ISA/
    support for PCMCIA devices? Certainly not me .

    --
    Lew Pitcher

    Master Codewright and JOAT-in-training
    Registered Linux User #112576 (http://counter.li.org/)
    Slackware - Because I know what I'm doing.


  5. Re: IRQ on PCMCIA Modem

    Guenter Resch wrote:
    > dhinds@sonic.net wrote ...


    >> My first guess is that you've configured your kernel with CONFIG_ISA
    >> disabled. Enable that and try again.


    > Unfortunately, enabling CONFIG_ISA did not change the situation.


    If you had to enable CONFIG_ISA then it seems unlikely that you also
    have another problem. Are you sure you installed the new kernel after
    reconfiguring and rebuilding? Double check with "uname -a".

    > When start with empty SERIAL_OPTS in /etc/pcmcia/serial.opts, the
    > modem is still running in polled mode (IRQ 0), when I force it to use
    > either IRQ 3 or 5 (SERIAL_OPTS="irq 5"; only one serial and parallel
    > port present on the system, so these two should be free), I get an
    > output like this:


    You cannot change the interrupt assignment for a PCMCIA device with
    setserial. It tells the serial driver to use that irq, but it does
    not reconfigure the PCMCIA socket. Thus, it won't ever work.

    -- Dave

  6. Re: IRQ on PCMCIA Modem

    dhinds@sonic.net wrote ...
    >> Unfortunately, enabling CONFIG_ISA did not change the situation.

    >
    > If you had to enable CONFIG_ISA then it seems unlikely that you also
    > have another problem. Are you sure you installed the new kernel after
    > reconfiguring and rebuilding? Double check with "uname -a".


    Yes, the newly compiled kernel was enabled ... I had already checked
    before. Nevertheless, it was great you said that because it made me
    check the whole thing with the RedHat standard kernel ... and guess
    what, ttyS1 got IRQ 3 assigned without passing on any SERIAL_OPTS. I
    just have to check at home if the modem really works ...

    If it does, I only need to find out what option I disabled in my custom
    kernel that is causing this problem ... hints, anyone?

    Regards,

    Guenter

  7. Re: IRQ on PCMCIA Modem

    Guenter Resch wrote ...
    > If it does, I only need to find out what option I disabled in my custom
    > kernel that is causing this problem ... hints, anyone?


    The problem was CONFIG_PNP disabled ... I just assumed that not to be
    neccessary for PMCIA as my PCMCIA NIC did very well with it. Thanks for
    these useful hints,

    Guenter

  8. Re: IRQ on PCMCIA Modem

    Guenter Resch wrote:
    > Guenter Resch wrote ...
    >> If it does, I only need to find out what option I disabled in my custom
    >> kernel that is causing this problem ... hints, anyone?


    > The problem was CONFIG_PNP disabled ... I just assumed that not to be
    > neccessary for PMCIA as my PCMCIA NIC did very well with it. Thanks for
    > these useful hints,


    Hmmm, I do not see why this would make any difference.

    -- Dave


  9. Re: IRQ on PCMCIA Modem

    Hi,

    did you check whether you have ISA support enabled in your kernel?
    On my old Compaq 1130T, which has no cardbus slots but 16-bit PCMCIA,
    So if it is a pcmcia 16bit this might be the reason.

    I once forgot to compile in ISA support and no cards worked.
    I am not so sure about PNP, I havent enabled CONFIG_ISA and
    CONFIG_ISAPNP in my kernel and it works fine with network, modem, wlan.

    The IRQs on PCMCIA are assigned by cardmgr, AFAIK, ISAPNP has nothing to
    do with it, but if you enable ISAPNP, youŽll probably enable ISA too and
    so it works ...

    Greetz,
    Lutz

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