Want a little more battery life? CPU, it's time for a 'Deep Sleep' ...
Posted 25 December 2007 - 03:21 PM
After further investigation, I have discovered that the webcam's USB Composite Device controller is responsible for the CPU's lack of Deep Sleep. Take a look at the below graphs:
Graph Shows-> Non-existant C3/Deep Sleep state when "USB Composite Device" is enabled
Graph Shows-> "Active" Battery Saving C3/Deep Sleep state when "USB Composite Device" is disabled
What you need to do in order to 'unlock' the processor's C3/Deep Sleep state:
1) Install Microsoft's KB918005 "Battery Drain Patch" for XP SP2. Deep Sleep will not be possible without this update.
For the I can neither confirm nor deny eeePC XP users ;) I have provided a direct link to the update:
2) Disable the "USB Composite Device" in device manager.
Whenever you need to use the webcam you'll have to re-enable the "USB Composite Device". If time permits, I (or someone else :D) can make a tray utility that will allow you to toggle the device/webcam off and on.
I have not tested to see how significant the battery life gains are, but I have no doubt that we will get a few more minutes out of our eeePC battery :)
Posted 25 December 2007 - 03:55 PM
Gateway LT2104u - 2 gig ram
Windows 7 Starter
Posted 26 December 2007 - 06:47 AM
Posted 26 December 2007 - 09:25 AM
I had a few hours to spare after the Xmas feast , so I decided to make a simple .NET 2.0 tray app that interfaces with Microsoft's DevCon command-line Device Manager application in order to toggle the webcam's USB controller off/on.
You can download the eeePC Webcam Tray App at http://dastudio.net/...eePCCamTray.zip
Extract the 'eeePCCamTray' directory to your drive, double click on 'eeePCCamTray.exe' to launch the application. You should see a miniature version of the application icon in XP's notification tray.
The tray app is straightforward to use:
- Hovering your mouse over the icon in the tray displays a tooltip that lets you know whether or not your eeePC webcam is currently enabled or disabled.
- Right clicking on the icon will present you with either an Enable Webcam, or Disable Webcam option, and also a "Close" option.
You should create a shortcut to the application in "Start-> All Programs-> Startup", doing so will allow the application to be loaded up once Windows has started.
If the application does not load you likely need to download .NET 2.0 framework http://www.microsoft...&displaylang=en
If it still doesn't work (hopefully we all have the same webcam hardware)... well too bad :P
Edited by NoeeePC4MeWellMaybe..., 05 January 2008 - 01:53 PM.
Posted 26 December 2007 - 10:35 AM
Posted 26 December 2007 - 11:42 AM
Since using the tray app to disable the web cam, I definitely see an improvement in my fanless idle temperature. The temperature decreases when the webcam controller is disabled, while it slowly increases when enabled. I'm pretty positive that our battery life will be slightly improved (maybe +10/15 minutes).
Posted 26 December 2007 - 12:02 PM
Anybody up for doing some benchmarks and posting the results?
Posted 26 December 2007 - 12:27 PM
WiFi on battery power uptime is 1hr 31 minutes as reported by the Atheros Utility, and XP's battery memter has just switched to 60% remaining. My screen brightness has been at 50%, and I have my WiFi adaptor's Transmit Power Level set at 1 mW as mentioned in http://forum.eeeuser...pic.php?id=6408. I haven't played any mulitimedia during this usage period.
Posted 26 December 2007 - 12:46 PM
Posted 26 December 2007 - 01:41 PM
Battery meter switched to 20% remaining capacity after 2hrs 51 minutes w/WiFi On. There was a 5 minute period of heavy/constant WiFi usage when I copied a 900MB file from the network to a SDHC card. Unless the battery meter is acting up, I should get over 3 hrs w/WiFi On.
I can definitely say that my fanless eeePC feels MUCH cooler than it has ever been after being powered on for 5 hrs straight.
The battery completely drained, causing eeePC to shut itself off @ 3 hrs 15 minutes. As mentioned earlier, that's with Wifi on, and the screen brightness set at 50% :). I may have been able to get a minute or two more if I did not transfer that large file over WiFi to the SD card (which was only inserted for the duration of the file transfer).
Edited by NoeeePC4MeWellMaybe..., 26 December 2007 - 02:21 PM.
Posted 26 December 2007 - 06:24 PM
Could you speak more to the reduction in fan use? One of my few complaints about the Eee is the fan coming on and its noise.
If this patch and procedure can reduce fan use, I think it's very important and should go in the wiki with that as a caption (not to discount the other merits).
Thanks for your offering!
old: 4g Pearl - 1GB DDR2 - WinXP Pro
new: 1g 1000H
Posted 26 December 2007 - 07:58 PM
The C3 state enabler hotpatch is the single best trick to enable longer run-times and less fan usage. It's surprising that Asus didn't include it in the driver CD package.
This post should be sticky'ed for all WinXP users to see.
4g Surf - 2GB DDR2 - WinXP Pro
Posted 26 December 2007 - 09:01 PM
8g pearl white with xp2 and loving it
Posted 26 December 2007 - 11:46 PM
Gateway LT2104u - 2 gig ram
Windows 7 Starter
Posted 27 December 2007 - 12:00 AM
Do we know if this problem effects the original OS, Xandros?
Edited by Neodudeman, 27 December 2007 - 12:01 AM.
It is with me everywhere,
And does everything.
Posted 27 December 2007 - 12:44 AM
Posted 27 December 2007 - 02:31 AM
I'm unsure if it will reduce how often the CPU fan comes on after it has initially started since the BIOS turns the fan on once the CPU temp reaches 55 degrees, and does not turn it off until it drops to ~46 degrees, which for most of our eeePC's will be an impossible fan halting temperature reach. BUT, the XP patch+tray app should increase the time it takes the fan to come on after a "cold boot".
When I posted the battery life results earlier today, my eeePC was idling around 55 degrees C after 5+hrs of light-average WiFi use. In the past, having the fanless eeePC on for 4-5 hrs straight, never moving it a cooler surface, would result in an idle temp of about 62 degrees C and the case would feel very very warm.
One thing to keep in mind, is that even with the XP patch & tray app, whenever you are actively using a USB device C3 Deep Sleep state can never be obtained. So If you make a habit out of constantly playing movies from your SD card, your battery life will likely remain unchanged.
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