In exploring our issue with periodic system watchdog errors, I came across a baffling scenario. First I noticed that if the classmate was plugged in the watchdogs went away, so next I started exploring the setting of the “power options properties” (power options icon under control panel).
I found that I could set the “portable/laptop” scheme to identical settings as the “presentation” setting; however I would get ~20 watchdog errors in 5 minutes under the laptop scheme, but no errors under the presentation scheme. This is running the default code with no changes. It doesn’t appear to make a difference what the settings with each scheme are, rather just that the ‘portable/laptop’ selection gives watchdog errors while under battery power. I haven’t yet explored any of the other power option schemes.
Can any one duplicate this, or better yet, explain why this could be?
from my expirence with windows xp’s power management functions it allows you to set things like shutdown after so much time, sleep after so much time, etc. it may be that although these are identical the OS is changing the amount of processer power it is allowed to use on battery power, however i don’t know an offical test to confirm this so this is just a guess.
on a closing note, our team uses the “Always On” power management scheme
After a bit of online searching about power saving schemes I found my answer. From more tests of our Classmate/cRIO I found that I could get rid of the system watchdog errors when in “Portable/Laptop” and “Max Battery” power schemes while under battery power. All other schemes produced an average of 4 watchdog errors per minute. It didn’t matter what the HD/monitor/system standby settings were (I tried many, including NEVER), it just mattered which power scheme name I selected.
Intel has included a power saving scheme in some of their CPUs called SpeedStep (including our Classmate’s Atom processor). Based on which power scheme you select the CPU may get powered back to save battery power. In the two selections that elimated errors for me Microsoft overides the Intel scheme to control the CPU power.
My solution was to go into the BIOS and disable the SpeedStep and C-State options (under Advanced>>CPU Configuration). Since doing this I have run our system for over 2 hours in TeleOp mode with ZERO watchdog errors while trying all power schemes and with/without AC power.
Press the DEL key as the Classmate is booting up (I pressed multiple times not knowing the exact time needed to press it). Please post if this solution works for you…I’m very curious if this issue is limited to a small group or if it is widespread.
While I do not get any watchdog errors during TeleOp enabled mode, I am still seeing one system watchdog error when going from Autonomous Enable to Disabled, and one going from TeleOp Enabled to disabled.
While it may not be conclusive proof that the Intel SpeedStep BIOS setting was our issue of lost communication with our robot in multiple rounds at the preseason Suffield CT Scrimmage, we have competed 7 rounds today at the Hartford Regional with zero communcations issues (we have the Intel SpeedStep and C-State options in the Classmate BIOS disabled).