Request for BIOS Update to Address High DPC Latency Caused by ACPI.sys

[Mihir2001]

Dear HP Support Team,

I am writing to formally request a BIOS-level review and update to address a persistent high DPC latency issue related to ACPI.sys on my HP Pavilion Power 15 cb045wm laptop.

After extensive testing and troubleshooting, I have confirmed that the primary source of the latency spikes is ACPI.sys. These spikes significantly impact real-time audio performance and system responsiveness, making the system unsuitable for low-latency workloads such as audio production.

I have already attempted the following mitigation steps:

1. Disabled Realtek PCIe GbE Family Controller
2. Disabled Microsoft ACPI-Compliant Control Method Battery (this reduces latency but is not a viable long-term solution on a laptop)
3. Disabled and updated Intel Dynamic Platform and Thermal Framework drivers
4. Unparked all CPU cores
5. Enabled Ultimate Performance power plan
6. Disabled Link State Power Management
7. Clean-installed latest Intel and Nvidia graphics drivers (with and without DDU)
8. Disabled Dynamic Tick and Idle states
9. Turned off Core Isolation
10. Set Nvidia Power Management Mode to “Prefer Maximum Performance”
11. Disabled USB Selective Suspend
12. Clean Windows installation.
13. Disabling Windows Security and many more fixes.
14. Using Windows 10 instead of Windows 11 to avoid even more latency issues.

Despite these efforts, DPC latency spikes persist and continue to trace back to ACPI.sys.

Since ACPI.sys interacts directly with firmware-level ACPI tables and power management logic provided by the BIOS, this suggests the root cause may lie in firmware power management implementation, interrupt routing, or thermal/power state transitions.

Disabling the ACPI battery driver reduces latency, which further indicates that embedded controller polling or ACPI event handling may be contributing excessive interrupt load. However, disabling this driver is not a viable long-term solution on a portable system.

Given this, I respectfully request that HP engineering:

• Investigate ACPI table implementation and embedded controller behavior
• Review interrupt handling and power state transitions
• Evaluate firmware-level optimizations to reduce ACPI.sys DPC load
• Consider releasing a BIOS update to address this issue

Many users rely on HP systems for professional audio and real-time workloads, and resolving firmware-level DPC latency issues would significantly improve system reliability and performance.

I would appreciate escalation of this issue to the appropriate engineering team and feedback regarding whether a BIOS-level fix is being considered.

Thank you for your time and assistance.

Here, is my Latencymon test result (~23 mins).

[Deep_World]

Hi @Mihir2001,
 
Welcome to the HP Support Community!

Thanks for reaching out!

Sorry for the inconvenience caused and don’t worry let me help you.

Thank you for  providing such a detailed breakdown of the troubleshooting steps you’ve already taken. I completely understand how high DPC latency can be, especially when it interferes with real-time audio workloads. Your effort in isolating ACPI.sys as the primary contributor shows you’ve done very thorough testing.

Could you please share a few additional details:

• The current BIOS version installed on your HP Pavilion Power 15 cb045wm.
• The operating system build (Windows 10 version and build number).
• Whether the issue persists when the laptop is running only on AC power (with the battery temporarily removed, if possible).

In the meantime, here are a few troubleshooting steps worth trying while we gather more information:

• BIOS Reset: Enter BIOS setup and load default settings to rule out misconfigured firmware parameters.
• Chipset Drivers: Ensure the latest Intel chipset drivers are installed directly from HP’s support page for your model (not just from Intel).
• BIOS Update Check: Verify if a newer BIOS version is available for your system on HP’s support website https://support.hp.com/ .  Sometimes updates include ACPI/EC optimizations.
• Battery Calibration: Perform a full battery calibration cycle (charge to 100%, discharge fully, then recharge) to see if it reduces embedded controller polling.
• Minimal Hardware Test: Disconnect all external USB devices and disable Wi-Fi temporarily to check if ACPI event handling improves.

I hope this helps.

I'm glad I could help! 😊 If this resolved your issue, please mark it as "Accepted Solution" and click "Yes" on "Was this reply helpful?" Your feedback not only keeps us going but also helps others find the solution faster! 

Take care and have an amazing day ahead! 

Best regards,

Deep_World.