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Re: [linuxham] Multiport Serial Card Problems

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  • David Toombs
    Thanks for this John, Unfortunately this doesn t seem to work either, at least not on my Mint 14 PC. 73 s de Dave, G8FXM
    Message 1 of 4 , Jan 23, 2013
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      Thanks for this John,
      Unfortunately this doesn't seem to work either, at least not on my Mint 14 PC.

      73's de Dave, G8FXM

      On 23/01/13 01:49, John Phelps wrote:

      Hi all,

      Have more hopefully useful info for the serial issue :-)

      Quick Summary: 
      • The max number of Linux-kernel serial ports is normally 4 (defined when kernel is compiled)
      • This number can be over-ridden though by adding the kernel commandline parameter " 8250.nr_uarts=X " where X is an integer value.
        • how to add this new commandline parameter varies from Linux distro to Linux distro... also on some distros this is just " nr_uarts=X " ...
        • No need to recompile kernel to add support for more serial ports.
      Hopefully adding this kernel commandline parameter clears the issue.

      ~ John 


      On Sun, Jan 20, 2013 at 10:31 AM, CIW308 VE6OH <ssc@...> wrote:

      There was an issue - long time ago - with some Kernels not supporting
      more that, I think, 4 com ports. You may have to rebuild the Kernel
      with support for more com ports.


      On 2013-01-20 11:27, David Toombs wrote:
      > Hi All,
      > I'm still getting some strange results with my WCH Group Multi Port
      > Serial Card card.
      > setserial returns the following:
      > /dev/ttyS4, UART: 16550A, Port: 0xcc20, IRQ: 19
      > /dev/ttyS5, UART: 16550A, Port: 0xcc28, IRQ: 19
      > /dev/ttyS6, UART: 16550A, Port: 0xcc30, IRQ: 19
      > /dev/ttyS7, UART: 16550A, Port: 0xcc38, IRQ: 19
      > ttyS4 and ttyS5 do not work at all. these are the additional ports
      > physically provided by the expansion bus.
      > ttyS6 and ttyS7 do work as expected in CQRLog i.e. if I configure
      > either, they both work.
      > however in FLDIGI by setting rig control to either ttyS6 or ttyS7,
      > FLDIGI works irrespective of which com port I actually connect the rig
      > too i.e. if I physically connect to ttyS6 a FLDIGI rig control setting
      > of ttyS6 or ttyS7 will work and visa versa.
      > Therefore maybe there is a problem with FLDIGI in addressing PCI serial
      > cards sharing a common IRQ maybe? I suggest this only as CQRLog works as
      > expected. Id appreciate hearing from anyone else who has a similar set
      > up who can confirm my findings.
      > I'm seeing reference to set_multiport via much googling, but havnt
      > worked out if I should be using this and how to use it? If anyone can
      > suggest a reason as to why ttyS4 and ttyS5 do not work wither either
      > CQRLog or FLDIGI or advise on how I set set_multiport, I'd also be very
      > grateful. I cant find any reason why these ports should not be working?
      > Note this card works flawlessly in Windows Vista so I don't suspect a
      > hardware failure.


      J. T. (Mitch) Mitchell
      Amateur Radio VE6OH RAC Director - Alberta, NWT, Nunavut
      Email mitch@...
      Mobile Cellular 780 446 8958

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