Intel Core Duo USB Issue: A Mischaracterized Bug
by Anand Lal Shimpi on February 13, 2006 1:40 PM EST- Posted in
- Laptops
Final Words
First of all, it's important to characterize the impact of the USB 2.0 asynchronous scheduler bug on both Core Duo and Pentium M based systems. Using the Lenovo T60 and T43 as comparison points, we found that without the fix, adding a bus-powered USB device such as a memory stick reduced battery life anywhere from 18 - 28%. In the case of the T43, a 28% reduction in battery life for simply plugging in a USB 2.0 device is beyond ridiculous. In the case of both notebooks, applying Microsoft's fix gives you almost all of your battery life back. The only decrease is due to actual power used by the device and any polling that may be happening as a result of the device being installed.
It is also extremely important that we point out the existence of this bug on all of the platforms that we tested; in other words, this is not exclusively a Core Duo problem. In fact, in the case of the T60/T43, the Sonoma based T43 actually lost a larger percentage of its battery life due to the asynchronous scheduler bug than the Napa based T60. We saw the same results with the ASUS notebooks. With only the integrated USB 2.0 camera connected, the ASUS Napa notebook lost 17% of its battery life due to the bug, while the Sonoma based W5A lost 25.5%. Once again, implying that this is a Core Duo issue alone is simply incorrect; the problem affects Sonoma platforms just as much, if not more, than Core Duo platforms. Based on the results that we've seen in our perfmon analysis, we tend to believe Microsoft's assessment that the problem would exist on any system that spent any time in C3 or lower power states.
Thankfully, the Microsoft fix does seem to work pretty well. The only downside is that the problem re-appears after bringing your notebook out of stand-by. Although a simple reboot will fix the problem once more, it's not a practical long term solution. Unfortunately, we have absolutely no idea when a true fix will be put in place. Until Microsoft releases a fix, we can only suggest that all notebook users, regardless of your CPU, either implement the temporary fix that we outlined in this article or be very conscious of leaving USB 2.0 devices connected while on battery power.
First of all, it's important to characterize the impact of the USB 2.0 asynchronous scheduler bug on both Core Duo and Pentium M based systems. Using the Lenovo T60 and T43 as comparison points, we found that without the fix, adding a bus-powered USB device such as a memory stick reduced battery life anywhere from 18 - 28%. In the case of the T43, a 28% reduction in battery life for simply plugging in a USB 2.0 device is beyond ridiculous. In the case of both notebooks, applying Microsoft's fix gives you almost all of your battery life back. The only decrease is due to actual power used by the device and any polling that may be happening as a result of the device being installed.
It is also extremely important that we point out the existence of this bug on all of the platforms that we tested; in other words, this is not exclusively a Core Duo problem. In fact, in the case of the T60/T43, the Sonoma based T43 actually lost a larger percentage of its battery life due to the asynchronous scheduler bug than the Napa based T60. We saw the same results with the ASUS notebooks. With only the integrated USB 2.0 camera connected, the ASUS Napa notebook lost 17% of its battery life due to the bug, while the Sonoma based W5A lost 25.5%. Once again, implying that this is a Core Duo issue alone is simply incorrect; the problem affects Sonoma platforms just as much, if not more, than Core Duo platforms. Based on the results that we've seen in our perfmon analysis, we tend to believe Microsoft's assessment that the problem would exist on any system that spent any time in C3 or lower power states.
Thankfully, the Microsoft fix does seem to work pretty well. The only downside is that the problem re-appears after bringing your notebook out of stand-by. Although a simple reboot will fix the problem once more, it's not a practical long term solution. Unfortunately, we have absolutely no idea when a true fix will be put in place. Until Microsoft releases a fix, we can only suggest that all notebook users, regardless of your CPU, either implement the temporary fix that we outlined in this article or be very conscious of leaving USB 2.0 devices connected while on battery power.
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krwilsonn - Wednesday, February 15, 2006 - link
I just read their new article and apparently they were tipped off by some "insider" about the problem and then went ahead and "discovered" and published it. That is what it says at the end of their article, anyway. Their forum thread that is linked has some comments from an editor or someone that are also interesting. I'm sure everyone is checking it out but for those that haven't you should for the sheer humor of it.mino - Tuesday, February 14, 2006 - link
1.) Installed new hp6220 custom configured an hour ago.Platform i915G - Sonoma
Provided Perfmon detects C3 correctly (showing curve around 98% at idle) this system may not bee affected.
I've installed HP's "System Enhancements Disk" package, so some workaround by HP may have been included. (the regfix is not present)
However I have no way to prove Perfmon is correct.
2.) nx6125 I've upgraded from home to Pro last week so it is HP install just a little sripped one
the system spend around 96% of its time at idle in C1, seems wierd to me. No time is spent in C3 also. Maybe somne HP stuff keep the CPU busy.
Both systems are used with Bluetooth mouse via an integrated adapter.
mino - Tuesday, February 14, 2006 - link
Just now I observed on nx6125 that the moment Intellimouse Explorer for Bluetooth goes into power save mode (after ~1 minute of inactivity) Turion goes from 96% in C1 to 96% in C2.Strange as it may seem nothing like this happens on Sonoma platform. I sense ATI SB400 does have something say about it.
Another thing is that the moment CPU starts using C2 intensively, the idle power consumption goes from ~15.6W to 13.2W which is pretty serious amount of power wasted.
Anand, I suggest you do not waste your time by testing battery life when you revisit this issue, to prove assumptions you may use Perfmon's Battery Drain counter.
HMM, funny is, the nc6220 does not show the battery counter present in Perfmon.
mino - Tuesday, February 14, 2006 - link
WE MISS EDIT !sripped == stripped
;D
artifex - Tuesday, February 14, 2006 - link
as soon as you get an MBP in for testing :)zsouthboy - Tuesday, February 14, 2006 - link
Not that its as big a deal for desktops, but mine seems to be doing the same thing when my USB 2.0 mouse/kb is plugged in...krwilsonn - Tuesday, February 14, 2006 - link
Are you being serious??kmmatney - Tuesday, February 14, 2006 - link
Yeah, I've noticed my Prescott's been running a little hot as well. Damn USB 2.0!blwest - Tuesday, February 14, 2006 - link
Yay, yet another "feature". If you run Microsoft Winders, we gurantee shorter battery life.dualathlon - Tuesday, February 14, 2006 - link
Hi, i own an dell inspiron 9300, pen M 760, geforce 6800go. When i enable that registry key, i experience heavy pointer delay when playing Counter Strike Source. I tried both logitech mx510 (wired) and logitech mx900 (bluetooth wireless, paired with dell internal BT and logitech hub as well).I see no delay in office apps, FYI. I haven't test battery life with that key though.