Comment 46 for bug 1087519

OK, I tried both lines. System would not boot with "pci=routeirq" added. It would boot with "pci=nocrs", but again ttyS4 would not work.

The way your previous message reads is a bit confusing to me. By "(for test if works)", do you mean to test if it will boot, or test if the serial port works? If the serial port should have worked, I'm out of luck again.

I guess the addition by editing the active grub lines is just to test for that one start if the system will operate with either one of the additions, and to determine which one will work? BTW, the line in the active grub was much different from either GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" or - GRUB_CMDLINE_LINUX="", but it did contain both quiet and splash.

Please confirm or not that "pci=nocrs" is just temporary in the active (by pressing shift, then escape) grub screen, and will disappear on the next boot.

My best guess now would be to:
- add "pci=nocrs" and the rest of your line to the "GRUB_CMDLINE_LINUX="", giving me
"GRUB_CMDLINE_LINUX="8250.nr_uarts=5 pci=nocrs" in /etc/default/grub
- run sudo "update-grub" in Terminal

But I have two "GRUB_CMDLINE_LINUX" lines. They are :
- GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
- GRUB_CMDLINE_LINUX=""

Please confirm the correct one to add to is GRUB_CMDLINE_LINUX=""

Thanks!