Hi Level1Techs,
Does anyone here still use the rcu_nocbs= kernel boot argument?
I’ve been on Ubuntu 18.04 with kernel 4.15.0_20 since Monday and haven’t noticed any of the issues this was supposed to fix.
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Oh, I might have “fixed” that by turning off C-States in the UEFI in the past.
But I have been on 4.15 or newer for a while now so …
Hmm, I’m on the ROG Zenith Extreme X399 motherboard with BIOS version 1003.
With this BIOS version the change log mentions this:
ROG ZENITH EXTREME BIOS 1003
1. Update AGESA Code to 1.0.0.5
Note: Global C-States can only be set in Enabled or Auto mode. Do not update to BIOS 1003 if you wish to set Global C-state to "Disabled".
So I cannot disable C-States with this BIOS revision. I see the following being logged at boot which seems to be associated:
[ 0.910284] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.910350] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.910400] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.910511] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.910615] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.910704] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.910758] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.910849] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.910940] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.911035] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.911129] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.911218] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.911302] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.911387] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.911434] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.917270] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.924054] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.924154] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.924210] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.924266] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.924356] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.924452] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.924542] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.924630] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
Currently running kernel version 4.16.18:
Linux arakasi 4.16.18-1-MANJARO #1 SMP PREEMPT Tue Jun 26 15:27:59 UTC 2018 x86_64 GNU/Linux
I’m wondering if I will need to enable the rcu_nocbs=0-23 kernel boot parameter for this board and a TR 1920x because I cannot disable C-States.
Any thoughts?