Intel D2500CC motherboard and strange RS232/UART behavior

From: Lev Serebryakov <lev_at_FreeBSD.org>
Date: Sun, 7 Apr 2013 17:20:16 +0400
Hello, Freebsd-current.

  I've built new router based on Intel D2500CC motherboard. It contains
 four (!) UARTs. Two of them are D-SUB9 on back panel, two others are
 only headers.
  This motherboard contains PS/2 keyboard and VGA too.

  I'm trying to get com console on one of D-SUBs.

  All UARTs are detected:

========================
uart0: <16550 or compatible> port 0x3f8-0x3ff irq 3 flags 0x10 on acpi0
uart0: console (115200,n,8,1)
uart1: <16550 or compatible> port 0x2f8-0x2ff irq 4 on acpi0
uart2: <16550 or compatible> port 0x2e8-0x2ef irq 3 on acpi0
uart3: <16550 or compatible> port 0x2e0-0x2e7 irq 4 on acpi0
========================

(but I don't know which UART corresponds to which connector)

 I have /boot.config:
========================
-D -S115200
========================

  And /boot/loader.conf:
========================
boot_serial="YES"
console="comconsole"
comconsole_speed="115200"
========================

  Also, "/etc/ttys" has all 4 (!) ttys enabled:
========================
ttyu0   "/usr/libexec/getty std.115200" xterm   on  secure
ttyu1   "/usr/libexec/getty std.115200" xterm   on  secure
ttyu2   "/usr/libexec/getty std.115200" xterm   on  secure
ttyu3   "/usr/libexec/getty std.115200" xterm   on  secure
========================

  But I don't see ANYTHING on ANY of two DSubs, when connect them to
 other computer with serial NULL modem cable. Nothing at all -- no
 boot progress, no getty prompt, nothing.

  Other strange thing is, that only two of four gettys has terminals:

========================
> ps -ax | grep getty
1731  -  I    0:00.00 /usr/libexec/getty std.115200 ttyu1
1733  -  I    0:00.00 /usr/libexec/getty std.115200 ttyu3
1730 u0  Is+  0:00.00 /usr/libexec/getty std.115200 ttyu0
1732 u2  Is+  0:00.00 /usr/libexec/getty std.115200 ttyu2
1729 v0  Is+  0:00.00 /usr/libexec/getty Pc ttyv0
1748  0  S+   0:00.00 grep getty
========================

  I'm sure, that COM port on other system and nullmodem cable is Ok,
 because I used them to have serial console on my precious router,
 Sokeris net5501-based, and it works perfectly with almost same
 config. Two differences was, that I had "-h -S115200" in /boot.config
 and I had only one getty on ttyu0.

  What do I do wrong?

-- 
// Black Lion AKA Lev Serebryakov <lev_at_FreeBSD.org>
Received on Sun Apr 07 2013 - 11:20:20 UTC

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