The bug causes "Napa" platform to consume abnormally high power when a device is connected to any of its USB 2.0 ports. It easily amounts to a loss of about one hour of precious battery time.
The power issue has prevented Intel from achieving the goal of four to five hours of battery life for its Core Duo 945 GM chipset.
Intel has confirmed that this was caused by a Microsoft driver bug, the worst part is that this bug was known to Microsoft for some time, but they nonchalantly kept it from the public view.
Intel's ICH7-M Southbridge
Problem :
The problem has been traced to the way the currently available version of the ICH7-M Southbridge communicates with Microsoft's ACPI driver, this is what lies at the heart of the power drain issue.
Microsoft attributed the cause to a misbehaving driver included in Windows XP SP2. Specifically, the Advanced Configuration and Power Interface (ACPI) driver, which is part of the operating system's power management scheme for USB 2.0
Issue in detail :
The issue, according to Microsoft, concerns the asynchronous scheduler component - a part of the USB 2.0 driver that determines when devices can access local memory. With the revision to that driver implemented in Windows XP Service Pack 2, the scheduler can inadvertently be left running.
As a result, Windows' internal task scheduler (a separate item) treats the asynchronous scheduler as a running process involving the attached device, and thus stops itself from ever giving the processor the signal to power down, or power lower - to slip into one of its ACPI sleep states.
Because the scheduler is running, Windows thinks the system is continually busy. As a result, the computer can use more battery power.
Solution :
The solution to the matter could be simple, a simple addition of a single key to the Windows System Registry.
The weird thing is why only Core Duo/945-based platform provoked the error and not the Sonoma or the AMD/ATI Radeon platforms.
However, the reason that one notebook is impacted by the bug and the other is not, may be be that there are several more components that can cause excessive power consumption through USB 2.0.
End user :
Buyers of Core Duo-based systems may find themselves implementing a fix, which is not necessarily easy for an amateur user, unless Microsoft makes it available as a "patch" that installs automatically.
Intel also is working to fix the issue by itself.
If the patch can be as simple as a modification to the registry, the question arises why Microsoft hasn't issued a registry patch. Microsoft said it is investigating and looking into this issue.
The power issue has prevented Intel from achieving the goal of four to five hours of battery life for its Core Duo 945 GM chipset.
Intel has confirmed that this was caused by a Microsoft driver bug, the worst part is that this bug was known to Microsoft for some time, but they nonchalantly kept it from the public view.
Intel's ICH7-M Southbridge
Problem :
The problem has been traced to the way the currently available version of the ICH7-M Southbridge communicates with Microsoft's ACPI driver, this is what lies at the heart of the power drain issue.
Microsoft attributed the cause to a misbehaving driver included in Windows XP SP2. Specifically, the Advanced Configuration and Power Interface (ACPI) driver, which is part of the operating system's power management scheme for USB 2.0
Issue in detail :
The issue, according to Microsoft, concerns the asynchronous scheduler component - a part of the USB 2.0 driver that determines when devices can access local memory. With the revision to that driver implemented in Windows XP Service Pack 2, the scheduler can inadvertently be left running.
As a result, Windows' internal task scheduler (a separate item) treats the asynchronous scheduler as a running process involving the attached device, and thus stops itself from ever giving the processor the signal to power down, or power lower - to slip into one of its ACPI sleep states.
Because the scheduler is running, Windows thinks the system is continually busy. As a result, the computer can use more battery power.
Solution :
The solution to the matter could be simple, a simple addition of a single key to the Windows System Registry.
The weird thing is why only Core Duo/945-based platform provoked the error and not the Sonoma or the AMD/ATI Radeon platforms.
However, the reason that one notebook is impacted by the bug and the other is not, may be be that there are several more components that can cause excessive power consumption through USB 2.0.
End user :
Buyers of Core Duo-based systems may find themselves implementing a fix, which is not necessarily easy for an amateur user, unless Microsoft makes it available as a "patch" that installs automatically.
Intel also is working to fix the issue by itself.
If the patch can be as simple as a modification to the registry, the question arises why Microsoft hasn't issued a registry patch. Microsoft said it is investigating and looking into this issue.