Intel D2500CC motherboard and strange RS232/UART behavior

[Lev Serebryakov]

Hello, Jürgen.
You wrote 24 мая 2013 г., 23:15:17:

WJ> According to the ACPI of the board, uart0 and uart 2
WJ> use IRQ 3 and
WJ>      IRQ (Edge, ActiveLow, Shared, )
WJ>        {3}
WJ> uart1 and uart3 use IRQ 4
WJ>      IRQ (Edge, ActiveLow, Shared, )
WJ>        {4}

WJ> ioapic_config_intr is called with trig == INTR_TRIGGER_EDGE and
WJ>  pol == INTR_POLARITY_LOW.

WJ> The combinatation of Edge and ActiveLow seems kind of broken.
WJ> Forcing the polarity in ioapic_config_intr to INTR_POLARITY_HIGH
WJ> and disabling uart 2 and uart 3 results in two working serial
WJ> interfaces.
WJ> So what is the correct fix to this?
    I've tried to disable ACPI access to these UARTs at all, then only
  two of them are detected, but they don't work either. And I cannot
  disable 2 and 3, as screen I have attached to this box (old IBM-made
  LCD from register/cashier machine, which works perfectly with FreeBSD
  default text console on this MoBo) cannot show text (!) BIOS setup
  screen to me -- it shows only blue noise and looks like compeltely
  out-of-sync.  I need to bring this box to some other dispaly and try
  to disable these two UARTs AND disable ACPI for them with loader
  tunable.

-- 
// Black Lion AKA Lev Serebryakov <lev at FreeBSD.org>