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MC82
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Serious bug HP Pavilion dv7- last BIOS/drivers - ACPI.sys constantly hangs DPCs for 4.4 milliseconds

HP Recommended
pavilion dv7
Microsoft Windows 7 (32-bit)

 

I have a Pavillion dv7 and recently I bought a traktor s5:

 

Reported issues with HP Pavilion ddv7, Intel i7, beats audio equipped laptops,

The OS is Windows 7 Home Premium 64-bit.

 

The issues were audible dropouts while using the software and USB audio interfaces we make.

 

The computer suffers from a DPC latency bottleneck, that is triggered constantly in the OS driver ACPI.sys.

(DPC is scheduled work from drivers (Deferred Procedure Call.) )

 

Every DPC scheduled by every driver must always finish quick (within 100 microseconds), or it causes a bug that acts as a bottleneck. When a long DPC runs in one driver, all other drivers are often necessarily paused, so on a machine that behaves in the reported way, Windows can not reliably service any drivers that need to run more often than once every 3-4 milliseconds.

 

Low latency is necessary for all home recording, DAW, music application, software synth applications, as well as pro audio interface hardware drivers.

 

Due to the bottleneck, these use cases all suffer from heavy sound artifacts of over/underruns to the audio interface driver. This includes our products but also any other low latency software and USB audio interfaces.

 

The HP Pavilion dv7 behaves this way from factory, and no matter what drivers are disabled or updated.
I have run all critical updates to the Windows 7 Home Premium 64-bit installation.

I have downloaded and installed all driver updates from HP support.

Finally I also downloaded the BIOS update that available at HP support.

I have also followed several guides to resolve such issues, including prevailing advice to disable the "ACPI Compliant Control Method Battery" driver in Device Manager (Edit: Filled in the name of the driver.)

 

Nothing helps the original issue.

 

I guess it's a BIOS-bug that is yet to be resolved by HP or their BIOS partner for this product.

I have the computer factory reset and ready for testing your solution, when it becomes available.

As it is now, we have to warn our users of such systems due to their unusable latency.

 

 

 

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Sparkles1
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Hi @MC82

 

 I have brought your issue to the attention of an appropriate team within HP. They will likely request information from you in order to look up your case details or product serial number. Please look for a private message from an identified HP contact. Additionally, keep in mind not to publicly post serial numbers and case details. If you are unfamiliar with how the Forum's private message capability works  please review this link. First Time Here? Learn How to Post and More

 

Sparkles1

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