bstreiff

[NOTE: this is mostly a collection of notes and not quite a specification nor an implementation thereof]

Predictable Serial Port Names

"How do I identify what I should open() for my RS-232 or RS-485 serial port?" is a surprisingly difficult question to answer on Linux.

You might think that "/dev/ttyS0, /dev/ttyS1, etc are my serial ports in order, right?" and the answer to that is Maybe.

bstreiff

[
  {
    "name": "Sun Type M",
    "author": "bstreiff",
    "switchMount": "cherry",
    "switchBrand": "cherry",
    "switchType": "MX1A-G1xx"
  },
  [
    {

bstreiff

[
  {
    "name": "XBAND Genesis Keyboard",
    "author": "Catapult Entertainment",
    "background": {
      "name": "PBT Black",
      "style": "background-image: url('/bg/plastic/pbt-black.png');"
    }
  },
  [

bstreiff

[
  {
    "name": "XBAND SNES Keyboard",
    "author": "Catapult Entertainment",
    "background": {
      "name": "PBT Black",
      "style": "background-image: url('/bg/plastic/pbt-black.png');"
    }
  },
  [

bstreiff

[
  {
    "backcolor": "#d6d5d0",
    "name": "Sun Type 6 - UNIX Layout",
    "author": "Sun Microsystems",
    "radii": "10px"
  },
  [
    {
      "c": "#a8a6a0",

bstreiff

[
  {
    "name": "Sun Type M",
    "author": "bstreiff",
    "switchMount": "cherry",
    "switchBrand": "cherry",
    "switchType": "MX1A-G1xx"
  },
  [
    {

bstreiff

# note: I have lightly preprocessed this trace to symbolicate the 'op' field
# for sys_futex calls.
#
# tracing configuration:
#   for x in "task" "migrate" "sched" "syscalls"; do
#      echo 1 > /sys/kernel/debug/tracing/events/$x/enable
#   done

LV_ESyse-1960    1d...2.. 1338906100002us : sched_switch: prev_comm=LV_ESyse_Thr3 prev_pid=1960 prev_prio=93 prev_state=S ==> next_comm=LV_Occurrence next_pid=1918 next_prio=93
LV_Occur-1918    1....1.. 1338906100008us : sys_futex -> 0x0

bstreiff

fixup_pi_state_owner (uaddr=0x120ad38, argowner=0x0 <irq_stack_union>, q=<optimized out>, q=<optimized out>)
    at /home/bstreiff/git/linux-rmb-hack/kernel/futex.c:2317
2317    /home/bstreiff/git/linux-rmb-hack/kernel/futex.c: No such file or directory.
(gdb) bt
#0  fixup_pi_state_owner (uaddr=0x120ad38, argowner=0x0 <irq_stack_union>, q=<optimized out>, q=<optimized out>)
    at /home/bstreiff/git/linux-rmb-hack/kernel/futex.c:2317
#1  0xffffffff810c0001 in fixup_owner (uaddr=<optimized out>, q=<optimized out>, locked=0)
    at /home/bstreiff/git/linux-rmb-hack/kernel/futex.c:2454
#2  0xffffffff810c1000 in futex_wait_requeue_pi (uaddr=<optimized out>, flags=<optimized out>, val=<optimized out>,
    abs_time=<optimized out>, uaddr2=<optimized out>, bitset=<optimized out>)