[Bug 2126636] Re: ACPI interrupt storm on Asus [Your Exact Laptop Model] causes 100% CPU, `acpi=noirq` workaround breaks audio

Solution Found: Disable GPE 0x6F

After months of living with this bug, I finally found a targeted fix
that resolves the 100% CPU usage without breaking sound or any other
functionality.

Root cause: GPE (General Purpose Event) 0x6F fires continuously because
the BIOS fan status method \_SB.PC00.LPCB.H_EC.TFN1._FST references a
symbol CFSP that doesn't exist in the ACPI tables. Each failed call
triggers another interrupt, creating the storm visible in
/proc/interrupts (113+ million hits on IRQ 9).

Diagnosis:

# Check which GPE is responsible for the storm:
cat /sys/firmware/acpi/interrupts/gpe_all # shows millions
cat /sys/firmware/acpi/interrupts/gpe6F # same number = culprit

Immediate fix (no reboot needed):

echo "disable" | sudo tee /sys/firmware/acpi/interrupts/gpe6F

CPU usage drops to normal instantly. Sound, EC, keyboard, trackpad,
everything else works fine. GPE 0x6E (the EC) is unaffected.

Permanent fix (survives reboot):

Create /etc/systemd/system/disable-gpe6f.service:

[Unit]
Description=Disable ACPI GPE 0x6F (broken fan status on Asus ExpertBook P3605CVA)
After=sysinit.target

[Service]
Type=oneshot
ExecStart=/bin/bash -c 'echo "disable" > /sys/firmware/acpi/interrupts/gpe6F'

[Install]
WantedBy=multi-user.target


Then enable it:

sudo systemctl daemon-reload
sudo systemctl enable disable-gpe6f.service


Environment: Kernel 6.18.7 on Ubuntu, but this should work on any kernel version since the issue is in the ASUS BIOS ACPI tables (P3605CVA BIOS version 302).

Note: The proper fix would be for ASUS to release a BIOS update that
defines the missing CFSP symbol, or for the kernel to handle the
AE_NOT_FOUND error more gracefully instead of letting the GPE re-fire
indefinitely. Until then, disabling GPE 0x6F is a clean workaround with
no side effects.

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https://bugs.launchpad.net/bugs/2126636

Title:
ACPI interrupt storm on Asus [Your Exact Laptop Model] causes 100%
CPU, `acpi=noirq` workaround breaks audio

Status in linux package in Ubuntu:
New

Bug description:
On my ASUSTeK COMPUTER INC. ASUS EXPERTBOOK P3605CVA, a single CPU
core is constantly at 100% usage. The `ps` command shows this is
caused by `kworker/kacpi_notify` and `irq/9-acpi`.

The kernel log shows a recurring ACPI error:
`ACPI Error: Aborting method \_SB.PC00.LPCB.H_EC.TFN1._FST due to previous error (AE_NOT_FOUND)`

Troubleshooting Steps Taken:
- A BIOS update is not available from Asus.
- Upgrading to mainline kernel 6.17.0 did not fix the issue.
- The following kernel parameters did not fix the CPU issue: `acpi_rev_override=1`, `acpi_ec_poll=1`, `acpi_osi=! acpi_osi='Windows 2021'`.
- The `nolapic` parameter causes the system to hang on a black screen during boot.
- The `acpi=noirq` parameter successfully fixes the 100% CPU issue, but it causes the internal sound card ("Speaker - Raptor Lake-P/U/H cAVS") to disappear, resulting in no sound.

ProblemType: Bug
DistroRelease: Ubuntu 25.04
Package: linux-image-6.14.0-33-generic 6.14.0-33.33
ProcVersionSignature: Ubuntu 6.14.0-33.33-generic 6.14.11
Uname: Linux 6.14.0-33-generic x86_64
ApportVersion: 2.32.0-0ubuntu5.3
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: aurelien 2784 F.... pipewire
aurelien 2792 F.... wireplumber
/dev/snd/seq: aurelien 2784 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Thu Oct 2 16:57:29 2025
InstallationDate: Installed on 2025-10-01 (1 days ago)
InstallationMedia: Ubuntu 25.04 "Plucky Puffin" - Release amd64 (20250415.3)
MachineType: ASUSTeK COMPUTER INC. ASUS EXPERTBOOK P3605CVA
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.14.0-33-generic root=UUID=151bb0ce-de78-41e4-8bc4-09f7b8050d63 ro quiet splash crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M vt.handoff=7
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-6.14.0-33-generic N/A
linux-backports-modules-6.14.0-33-generic N/A
linux-firmware 20250317.git1d4c88ee-0ubuntu1.6
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/17/2025
dmi.bios.release: 5.32
dmi.bios.vendor: ASUSTeK COMPUTER INC. (Licensed by AMI, LLC.)
dmi.bios.version: P3605CVA.302
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: P3605CVA
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.ec.firmware.release: 3.17
dmi.modalias: dmi:bvnASUSTeKCOMPUTERINC.(LicensedbyAMI,LLC.):bvrP3605CVA.302:bd05/17/2025:br5.32:efr3.17:svnASUSTeKCOMPUTERINC.:pnASUSEXPERTBOOKP3605CVA:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnP3605CVA:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:sku:
dmi.product.family: ASUS EXPERTBOOK
dmi.product.name: ASUS EXPERTBOOK P3605CVA
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.

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