Cheap mobo that doesn't cause issues with Ubuntu.

[Ralf Mardorf]

On Wed, 15 Feb 2017 16:53:41 +0000, Liam Proven wrote:
>On 15 February 2017 at 09:06, Ralf Mardorf wrote:
>> At least one PCIe slot, one PCI slot and one USB port must have an
>> IRQ that isn't shared with anything else.  
>
>PCI should not be that hard to find. PCI-e is normal.
>
>A PS/2 port is most often found on gamers' motherboards today. Some
>extreme gamers feel that USB mice suffer from latency or jitter and
>prefer PS/2 mice. I think this is as completely untrue as homeopathy,
>but hey, their choice.

I want a PS/2 socket for the keyboard, because I'm using USB with
real-time priority for an audio device. I'm already using an USB mouse
and it could cause issues when I'm using my Focusrite Scarlett 18i20
2nd Gen a pro-sumer USB audio interface, instead of my RME HDSP AIO a
professional PCIe audio interface.

>On PCI systems, IRQ sharing is normal

Not for the mobo I'm using now. Any mobo that doesn't support an
individual IRQ for at least one PCI card and one PCIe card is
completely useless for me, since I need them for real-time audio, too.

The kernel seems to care a little bit about this, since on older
kernels PCIe shared the IRQ with my mobo's onboard graphics and new
kernels assign an individual IRQ to the graphics.

Sometimes it's possible to get rid of a shared IRQ, e.g. by
unbinding devices, I'm doing this by a script:

$ tail -75 /usr/local/sbin/rttune 

case $(basename $0) in
  tuning)      # script 2013-Apr-05 compatibility
    all="$all\n--no-misc\n--unbind";;
  tuning-rice) # script 2013-Apr-05 compatibility
    all="$all\n--no-envy\n--no-misc\n--unbind";;
  *)           # new
    all=""
    while [ "$1" ]; do
      case $1 in
      ""|--log-status)
        ;;
      --all)
        all="$all\n--no-envy\n--no-hdsp\n--no-misc\n--unbind";;
      --no-envy)
        all="$all\n--no-envy";;
      --no-hdsp)
        all="$all\n--no-hdsp";;
      --no-misc)
        all="$all\n--no-misc";;
      --unbind)
        all="$all\n--unbind";;
      *)
        all="\n--help";;
      esac
      shift
    done;;
esac

all=$(printf "$all" | sort -u)
for option in $all; do
  case $option in
  --no-envy) # TerraTec EWX 24/96
    sudo modprobe -r snd_ice1712;;
  --no-hdsp) # RME HDSPe AIO
    sudo modprobe -r snd_hdspm;;
  --no-misc) # Misc
    sudo modprobe -r firewire-ohci
    sudo modprobe -r firewire_core
    sudo modprobe -r ppdev # parallel port
    sudo modprobe -r lp    # printer
    # Not removed by script 2013-Apr-05
    sudo modprobe -r parport_pc
    sudo modprobe -r parport
    sudo modprobe -r pata_atiixp;;
  --unbind) # Unbinding devices
    cd /sys/bus/pci/drivers/ohci-pci
    test -h 0000:00:13.2 && printf "0000:00:13.2" | sudo tee unbind >/dev/null
    test -h 0000:00:13.4 && printf "0000:00:13.4" | sudo tee unbind >/dev/null;;
  *) # Help
    usage
    exit;;
  esac
done

# Log file
l="/var/log/tuning.log"
case $(basename $0) in tuning|tuning-rice)
  all="";;
esac
echo "$(basename $0) "$all                       | sudo tee $l >/dev/null
echo "# rtirq status           "                 | sudo tee -a $l >/dev/null
rtirq status                                     | sudo tee -a $l >/dev/null
echo "# grep 18: /proc/interrupts"               | sudo tee -a $l >/dev/null
grep 18: /proc/interrupts                        | sudo tee -a $l >/dev/null
echo "# grep usb /proc/interrupts | grep -v 18:" | sudo tee -a $l >/dev/null
grep usb /proc/interrupts | grep -v 18:          | sudo tee -a $l >/dev/null
echo                                             | sudo tee -a $l >/dev/null
printf "$(date) - $(uname -r) - "                | sudo tee -a $l >/dev/null
grep PRETTY_NAME /etc/os-release                 | sudo tee -a $l >/dev/null
printf "\n#\n\n"
cat $l
printf "\n#\n\n"

exit

>So many things might share the IRQ of any given device, and that IRQ
>could vary from one boot up to the next.

Not the mobo I'm using now and I doubt that anybody using the PC for
real-time tasks, music, CNC etc. wants to use such a PC.

Regards,
Ralf