Public bug reported:
After resuming from suspend, the CPU sometimes becomes locked at
approximately 544 MHz on all 16 logical CPUs. This makes the entire
system extremely slow.
The issue appears when the AC adapter state changes while the laptop is
suspended. In other words, the laptop resumes with a different AC power
state from the state it had when entering suspend.
The CPU remains locked at approximately 544 MHz even under full CPU
load. Changing the Ubuntu power profile between balanced and performance
does not resolve the issue.
Changing the AC adapter state once more after resume immediately
restores normal CPU frequency scaling. For example, when the system
resumes on battery in the affected state, connecting the AC adapter for
one or two seconds restores normal performance. The adapter can then be
disconnected again, and the CPU continues to operate normally on
battery.
Observed trigger sequences:
Sequence 1:
1. Connect the AC adapter.
2. Suspend the laptop, for example by closing the lid.
3. Disconnect the AC adapter while the laptop is suspended.
4. Resume the laptop while it is running on battery.
5. The CPU may remain fixed at approximately 544 MHz under full load.
Sequence 2:
1. Start with the laptop running on battery.
2. Suspend the laptop.
3. Connect the AC adapter while the laptop is suspended.
4. Resume the laptop while connected to AC power.
5. The CPU may again remain fixed at approximately 544 MHz.
The common trigger appears to be that the AC power state at resume
differs from the AC power state at suspend.
System information:
* Device: HP ZBook Power 16 inch G11 A Mobile Workstation PC
* Product number: 9A818AV
* CPU: AMD Ryzen 9 PRO 8945HS with Radeon 780M Graphics
* Ubuntu: 24.04.4 LTS
* Kernel: 7.0.0-28-generic
* The problem was also previously observed with kernel 6.17.0-35-generic
* BIOS: W85 Ver. 01.10.05, dated 2026-05-04
* Embedded controller firmware: 8.82
* KBC version: 08.52.00
* amd-pstate mode: active / amd-pstate-epp
* BIOS and other available firmware are up to date according to fwupdmgr
Kernel package information:
```
linux-image-7.0.0-28-generic:
Installed: 7.0.0-28.28~24.04.1
Candidate: 7.0.0-28.28~24.04.1
Version table:
*** 7.0.0-28.28~24.04.1 500
500 http://de.archive.ubuntu.com/ubuntu noble-updates/main amd64
Packages
500 http://security.ubuntu.com/ubuntu noble-security/main amd64 Packages
100 /var/lib/dpkg/status
```
The report was created using:
```
ubuntu-bug linux
```
Steps to reproduce:
1. Connect the AC adapter.
2. Suspend the laptop, for example by closing the lid.
3. Wait until the laptop has entered suspend.
4. Disconnect the AC adapter while the laptop is suspended.
5. Resume the laptop while it is running on battery.
6. When the slowdown occurs, create full CPU load, for example:
for i in $(seq 1 16); do yes > /dev/null & done
sleep 3
grep "cpu MHz" /proc/cpuinfo | sort -n
killall yes
7. All logical CPUs remain at approximately 544 MHz despite the full
load.
8. Change the power profile with:
powerprofilesctl set performance
9. The CPU remains locked at approximately 544 MHz.
10. Briefly reconnect the AC adapter.
11. Disconnect the adapter again and repeat the load test.
12. The CPUs now reach approximately 4.39 GHz.
The reverse trigger can also occur:
1. Suspend the laptop while it is running on battery.
2. Connect the AC adapter while the laptop is suspended.
3. Resume the laptop while connected to AC power.
4. The CPU may remain fixed at approximately 544 MHz.
Expected result:
The CPU should increase its frequency normally under load after resume,
regardless of whether the AC adapter state changed while the laptop was
suspended.
Actual result:
When the AC adapter state changes during suspend, the CPU may remain
locked at approximately 544 MHz after resume. Changing the Ubuntu power
profile does not help. Changing the AC adapter state again after resume
immediately removes the limitation and restores normal frequency
scaling.
Additional observations:
Before and after restoring normal performance by briefly connecting the
adapter, the following Linux-visible settings remain unchanged:
* powerprofilesctl profile: balanced
* ACPI platform profile: balanced
* amd-pstate status: active
* CPU boost: enabled
* scaling_max_freq: approximately 5.263 GHz
* cpuinfo_max_freq: approximately 5.263 GHz
* scaling_min_freq: approximately 1.101 GHz
Therefore, Linux reports that the CPU is permitted to reach its normal
maximum frequency even while the actual clock remains fixed at
approximately 544 MHz.
Before the recovery event, all 16 logical CPUs remain at approximately
544 MHz under full load. After briefly connecting and disconnecting the
AC adapter, the same load results in CPU frequencies of approximately
4.39 GHz.
The AC adapter event appears normally through the ACPI power-supply
interface as:
```
POWER_SUPPLY_NAME=AC
POWER_SUPPLY_TYPE=Mains
POWER_SUPPLY_ONLINE=1
```
After disconnecting the adapter, POWER_SUPPLY_ONLINE returns to 0 and
the battery reports Discharging, but normal CPU performance remains
restored.
The single attached evidence file contains:
* the CPU and power-management state before connecting AC
* the CPU and power-management state after connecting and disconnecting AC
* a before-and-after comparison
* the relevant udev power-supply events
This may be related to an incorrect power-limit state in the HP embedded
controller, AMD SMU/PMF, or the suspend/resume handling between the
kernel and platform firmware.
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-7.0.0-28-generic 7.0.0-28.28~24.04.1
ProcVersionSignature: Ubuntu 7.0.0-28.28~24.04.1-generic 7.0.12
Uname: Linux 7.0.0-28-generic x86_64
ApportVersion: 2.28.2-0ubuntu0.1
Architecture: amd64
CasperMD5json: {
CasperVersion: 1.498
CurrentDesktop: ubuntu:GNOME
Date: Thu Jul 30 11:27:18 2026
DistributionChannelDescriptor:
# This is the distribution channel descriptor for the OEM CDs
# For more information see
http://wiki.ubuntu.com/DistributionChannelDescriptor
canonical-oem-stella-jammy-amd64-20240528-857
InstallationDate: Installed on 2024-06-07 (783 days ago)
InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" -
pc-stella-jammy-amd64-20240528-857
LiveMediaBuild: Error: path contained symlinks.
MachineType: HP HP ZBook Power 16 inch G11 A Mobile Workstation PC
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-28-generic
root=UUID=061463ca-e16f-4d4d-a642-fb0ab9d66401 ro quiet splash 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-7.0.0-28-generic N/A
linux-backports-modules-7.0.0-28-generic N/A
linux-firmware 20240318.git3b128b60-0ubuntu2.27
SourcePackage: linux-hwe-7.0
UpgradeStatus: Upgraded to noble on 2025-04-08 (478 days ago)
dmi.bios.date: 05/04/2026
dmi.bios.release: 10.5
dmi.bios.vendor: HP
dmi.bios.version: W85 Ver. 01.10.05
dmi.board.name: 8C95
dmi.board.vendor: HP
dmi.board.version: KBC Version 08.52.00
dmi.chassis.type: 10
dmi.chassis.vendor: HP
dmi.ec.firmware.release: 8.82
dmi.modalias:
dmi:bvnHP:bvrW85Ver.01.10.05:bd05/04/2026:br10.5:efr8.82:svnHP:pnHPZBookPower16inchG11AMobileWorkstationPC:pvrSBKPFV3:rvnHP:rn8C95:rvrKBCVersion08.52.00:cvnHP:ct10:cvr:sku9A818AV:pfa103C_5336ANHPZBook:
dmi.product.family: 103C_5336AN HP ZBook
dmi.product.name: HP ZBook Power 16 inch G11 A Mobile Workstation PC
dmi.product.sku: 9A818AV
dmi.product.version: SBKPFV3
dmi.sys.vendor: HP
** Affects: linux-hwe-7.0 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
** Attachment added: "launchpad-combined-evidence.txt"
https://bugs.launchpad.net/bugs/2162127/+attachment/5987906/+files/launchpad-combined-evidence.txt
** Summary changed:
- HP ZBook Power 16 G11 A: CPU stuck at 544 MHz after resume on battery until
AC adapter is connected
+ HP ZBook Power 16 G11 A: CPU stuck at 544 MHz after resume when AC adapter
state changes during suspend
** Description changed:
- After resuming from suspend while running on battery, the CPU sometimes
- becomes locked at approximately 544 MHz on all 16 logical CPUs. This
- makes the entire system extremely slow.
-
- The problem persists even under full CPU load. Changing the Ubuntu power
- profile between balanced and performance does not resolve it.
-
- Briefly connecting the AC adapter, even for only one or two seconds,
- immediately restores normal CPU frequency scaling. The adapter can then
- be disconnected again and the CPU continues to operate normally on
+ After resuming from suspend, the CPU sometimes becomes locked at
+ approximately 544 MHz on all 16 logical CPUs. This makes the entire
+ system extremely slow.
+
+ The issue appears when the AC adapter state changes while the laptop is
+ suspended. In other words, the laptop resumes with a different AC power
+ state from the state it had when entering suspend.
+
+ The CPU remains locked at approximately 544 MHz even under full CPU
+ load. Changing the Ubuntu power profile between balanced and performance
+ does not resolve the issue.
+
+ Changing the AC adapter state once more after resume immediately
+ restores normal CPU frequency scaling. For example, when the system
+ resumes on battery in the affected state, connecting the AC adapter for
+ one or two seconds restores normal performance. The adapter can then be
+ disconnected again, and the CPU continues to operate normally on
battery.
+
+ Observed trigger sequences:
+
+ Sequence 1:
+
+ 1. Connect the AC adapter.
+ 2. Suspend the laptop, for example by closing the lid.
+ 3. Disconnect the AC adapter while the laptop is suspended.
+ 4. Resume the laptop while it is running on battery.
+ 5. The CPU may remain fixed at approximately 544 MHz under full load.
+
+ Sequence 2:
+
+ 1. Start with the laptop running on battery.
+ 2. Suspend the laptop.
+ 3. Connect the AC adapter while the laptop is suspended.
+ 4. Resume the laptop while connected to AC power.
+ 5. The CPU may again remain fixed at approximately 544 MHz.
+
+ The common trigger appears to be that the AC power state at resume
+ differs from the AC power state at suspend.
System information:
* Device: HP ZBook Power 16 inch G11 A Mobile Workstation PC
* Product number: 9A818AV
* CPU: AMD Ryzen 9 PRO 8945HS with Radeon 780M Graphics
* Ubuntu: 24.04.4 LTS
* Kernel: 7.0.0-28-generic
* The problem was also previously observed with kernel 6.17.0-35-generic
* BIOS: W85 Ver. 01.10.05, dated 2026-05-04
+ * Embedded controller firmware: 8.82
+ * KBC version: 08.52.00
* amd-pstate mode: active / amd-pstate-epp
* BIOS and other available firmware are up to date according to fwupdmgr
Kernel package information:
+ ```
linux-image-7.0.0-28-generic:
Installed: 7.0.0-28.28~24.04.1
Candidate: 7.0.0-28.28~24.04.1
Version table:
*** 7.0.0-28.28~24.04.1 500
500 http://de.archive.ubuntu.com/ubuntu noble-updates/main amd64
Packages
500 http://security.ubuntu.com/ubuntu noble-security/main amd64
Packages
100 /var/lib/dpkg/status
-
+ ```
The report was created using:
+ ```
ubuntu-bug linux
-
+ ```
Steps to reproduce:
- 1. Run the laptop on battery.
-
- 2. Suspend the system.
-
- 3. Resume the system.
-
- 4. When the slowdown occurs, create full CPU load, for example:
+ 1. Connect the AC adapter.
+
+ 2. Suspend the laptop, for example by closing the lid.
+
+ 3. Wait until the laptop has entered suspend.
+
+ 4. Disconnect the AC adapter while the laptop is suspended.
+
+ 5. Resume the laptop while it is running on battery.
+
+ 6. When the slowdown occurs, create full CPU load, for example:
for i in $(seq 1 16); do yes > /dev/null & done
sleep 3
grep "cpu MHz" /proc/cpuinfo | sort -n
killall yes
- 5. All logical CPUs remain at approximately 544 MHz despite the full
+ 7. All logical CPUs remain at approximately 544 MHz despite the full
load.
- 6. Change the profile with:
+ 8. Change the power profile with:
powerprofilesctl set performance
- 7. The CPU remains locked at approximately 544 MHz.
-
- 8. Briefly connect the AC adapter.
-
- 9. Disconnect the adapter again and repeat the load test.
-
- 10. The CPUs now reach approximately 4.39 GHz.
+ 9. The CPU remains locked at approximately 544 MHz.
+
+ 10. Briefly reconnect the AC adapter.
+
+ 11. Disconnect the adapter again and repeat the load test.
+
+ 12. The CPUs now reach approximately 4.39 GHz.
+
+ The reverse trigger can also occur:
+
+ 1. Suspend the laptop while it is running on battery.
+ 2. Connect the AC adapter while the laptop is suspended.
+ 3. Resume the laptop while connected to AC power.
+ 4. The CPU may remain fixed at approximately 544 MHz.
Expected result:
The CPU should increase its frequency normally under load after resume,
- regardless of whether the laptop is running on AC power or battery.
+ regardless of whether the AC adapter state changed while the laptop was
+ suspended.
Actual result:
- After some resumes on battery, every logical CPU remains locked at
- approximately 544 MHz. Changing the power profile does not help. A brief
- AC adapter connection immediately removes the limitation.
+ When the AC adapter state changes during suspend, the CPU may remain
+ locked at approximately 544 MHz after resume. Changing the Ubuntu power
+ profile does not help. Changing the AC adapter state again after resume
+ immediately removes the limitation and restores normal frequency
+ scaling.
Additional observations:
- Before and after connecting the adapter, the following Linux-visible
- settings remain unchanged:
+ Before and after restoring normal performance by briefly connecting the
+ adapter, the following Linux-visible settings remain unchanged:
* powerprofilesctl profile: balanced
* ACPI platform profile: balanced
* amd-pstate status: active
* CPU boost: enabled
* scaling_max_freq: approximately 5.263 GHz
* cpuinfo_max_freq: approximately 5.263 GHz
* scaling_min_freq: approximately 1.101 GHz
Therefore, Linux reports that the CPU is permitted to reach its normal
- maximum frequency even while the real clock remains fixed at
+ maximum frequency even while the actual clock remains fixed at
approximately 544 MHz.
+
+ Before the recovery event, all 16 logical CPUs remain at approximately
+ 544 MHz under full load. After briefly connecting and disconnecting the
+ AC adapter, the same load results in CPU frequencies of approximately
+ 4.39 GHz.
The AC adapter event appears normally through the ACPI power-supply
interface as:
```
POWER_SUPPLY_NAME=AC
POWER_SUPPLY_TYPE=Mains
POWER_SUPPLY_ONLINE=1
```
After disconnecting the adapter, POWER_SUPPLY_ONLINE returns to 0 and
the battery reports Discharging, but normal CPU performance remains
restored.
- I will attach (combined):
-
- * before.txt
- * after.txt
- * before-vs-after.diff
- * the udev power-supply event log
+ The single attached evidence file contains:
+
+ * the CPU and power-management state before connecting AC
+ * the CPU and power-management state after connecting and disconnecting AC
+ * a before-and-after comparison
+ * the relevant udev power-supply events
This may be related to an incorrect power-limit state in the HP embedded
controller, AMD SMU/PMF, or the suspend/resume handling between the
kernel and platform firmware.
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-7.0.0-28-generic 7.0.0-28.28~24.04.1
ProcVersionSignature: Ubuntu 7.0.0-28.28~24.04.1-generic 7.0.12
Uname: Linux 7.0.0-28-generic x86_64
ApportVersion: 2.28.2-0ubuntu0.1
Architecture: amd64
CasperMD5json: {
CasperVersion: 1.498
CurrentDesktop: ubuntu:GNOME
Date: Thu Jul 30 11:27:18 2026
DistributionChannelDescriptor:
- # This is the distribution channel descriptor for the OEM CDs
- # For more information see
http://wiki.ubuntu.com/DistributionChannelDescriptor
- canonical-oem-stella-jammy-amd64-20240528-857
+
+ # This is the distribution channel descriptor for the OEM CDs
+
+ # For more information see
+ http://wiki.ubuntu.com/DistributionChannelDescriptor
+
+ canonical-oem-stella-jammy-amd64-20240528-857
InstallationDate: Installed on 2024-06-07 (783 days ago)
InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" -
pc-stella-jammy-amd64-20240528-857
LiveMediaBuild: Error: path contained symlinks.
MachineType: HP HP ZBook Power 16 inch G11 A Mobile Workstation PC
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-28-generic
root=UUID=061463ca-e16f-4d4d-a642-fb0ab9d66401 ro quiet splash 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-7.0.0-28-generic N/A
- linux-backports-modules-7.0.0-28-generic N/A
- linux-firmware 20240318.git3b128b60-0ubuntu2.27
+ linux-restricted-modules-7.0.0-28-generic N/A
+ linux-backports-modules-7.0.0-28-generic N/A
+ linux-firmware 20240318.git3b128b60-0ubuntu2.27
SourcePackage: linux-hwe-7.0
UpgradeStatus: Upgraded to noble on 2025-04-08 (478 days ago)
dmi.bios.date: 05/04/2026
dmi.bios.release: 10.5
dmi.bios.vendor: HP
dmi.bios.version: W85 Ver. 01.10.05
dmi.board.name: 8C95
dmi.board.vendor: HP
dmi.board.version: KBC Version 08.52.00
dmi.chassis.type: 10
dmi.chassis.vendor: HP
dmi.ec.firmware.release: 8.82
dmi.modalias:
dmi:bvnHP:bvrW85Ver.01.10.05:bd05/04/2026:br10.5:efr8.82:svnHP:pnHPZBookPower16inchG11AMobileWorkstationPC:pvrSBKPFV3:rvnHP:rn8C95:rvrKBCVersion08.52.00:cvnHP:ct10:cvr:sku9A818AV:pfa103C_5336ANHPZBook:
dmi.product.family: 103C_5336AN HP ZBook
dmi.product.name: HP ZBook Power 16 inch G11 A Mobile Workstation PC
dmi.product.sku: 9A818AV
dmi.product.version: SBKPFV3
dmi.sys.vendor: HP
--
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https://bugs.launchpad.net/bugs/2162127
Title:
HP ZBook Power 16 G11 A: CPU stuck at 544 MHz after resume when AC
adapter state changes during suspend
To manage notifications about this bug go to:
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