[email protected] said: > Every build since 8.2.0 (last October) does this, if you go to the > Power control panel and turn on Automatic power management. For more > power saving by turning off the wifi chip, turn on Extreme power > management.
Neat. Thanks. Somehow I'd missed that. That page might be a nice place to put a check-box to turn off networking when active, either to save power when there are no other XOs around (or school servers or APs) or to make it airplane safe. (Is a switch like that good enough for airplanes?) ------- I've read http://wiki.laptop.org/go/Suspend_and_resume Could somebody give me an update? I though the goal was to go to sleep between keystrokes. A sleeping XO running 802 takes 1.6 seconds to respond to a ping. I assume waking up from a key or cursor are similar, but I can't measure them as easily. At the keyboard/cursor, I find that delay annoying. I might choose to live with it after a bit of practice if I really wanted longer battery life. ping to a sleeping xo consistently drops the second packet. It's acting like the module only has enough buffering for one packet. (It takes 1.6 second to wakeup. The second ping goes out after 1 second.) But only-one-buffer would probably screwup normal operations. Is the WiFi firmware doing anything different in the sleeping case? An XO (running 802) doesn't wakeup in response to a broadcast ARP looking for it. That's http://dev.laptop.org/ticket/3732 Network traffic doesn't seem to kick the don't-sleep timer. I tried to use ping to keep a system from going to sleep. It sends a packet every second, but the xo went to sleep occasionally: 2% packet loss and an occasional time of 1.6 seconds. I've seen several cases (over several days) where waking up or going to sleep gets stuck in a strange state. It's running, the network and cursor work, but the button to turn the backlight on doesn't do anything. Is there something I should look for to gather more info? I also saw another case where the radio got turned off. (Net didn't respond, LED was out, keyboard worked.) Is there an API and/or documentation for this area? (I'm interested in both the XO and Linux in general.) Can I setup a machine to wake up in 10 minutes? (For example, to maximize battery life while collecting data.) What happens to a program that calls sleep? Some quick shell hacking says if the system goes to sleep, the program doesn't get woken up until something else wakes up the system. That's going to break a lot of code. (but probably necessary/appropriate if you are running the type of code that polls every second.) What happens with arp and dhcp timers while an XO is sleeping? My straw man is that arp timers should time out, DHCP timers should wakeup the system so it can renew its lease. What can I do to help? -------- I'm interested in timekeeping. What sort of accuracy are people expecting for the time on their XO? All I can see in the control panel => Date & time is a way to select the time zone. Is there a way for a non-geek to manually set the time? I see that /etc/NetworkManager/dispatcher.d/time-sync calls ntpdate to try to set the time when a network comes up. What chunk of hardware keeps track of time while the XO is sleeping? I would have guessed the RTC/TOY clock, but ssh-ing in to an XO that was sleeping shows that hwclock and date are way off. Is there a counter in the EC? Can I read it from user code? (The RTC/TOY is a poor choice anyway since you can only read it to a second. You can do better than that by spinning until it ticks, but that's not appropriate for suspend/wakeup.) Does anybody know which timekeeping option the XO kernel is using? (Linux has several choices. I can probably find it by looking at the kernel config file and/or hacking in some printfs.) When auto-suspend is disabled, I see a drift rate of roughly 10 seconds in 24 hours on one particular system. That's 115 ppm, not good but not silly. It's a nice clean drift, what I expect if the crystal is slightly off frequency or the software is slightly off. When the XO goes to sleep and gets woken up once or twice every 5 minutes, the clock is much more "interesting". Offsets of 5 or 20 seconds are common. Typically it drifts with a sawtooth pattern, say losing 10 seconds over a few hours then changing direction, gaining a few seconds, then switching back... I haven't been able to sort out a pattern. ntpd doesn't like running on an xo with power savings enabled. I've seen it gain 200 seconds in under 8 hours. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ Devel mailing list [email protected] http://lists.laptop.org/listinfo/devel
