NetBSD power question

Hello,

I am buying a Jornada 720 and I'm considering running NetBSD on it. From what I've read, the battery drains in about 18 hours when suspended. Has this been fixed yet, either in 3.0 or in the bleeding-edge NetBSD sources? I really want to run NetBSD, but not if it's going to drain my batteries in a day. I can't seem to find a conclusive answer, only old messages or people who don't specify which version of NetBSD they tried.

It is a little better in newer versions, if I remember correctly, but we cannot do a full suspend, due to a limitation in the processor. We are thinking up a sort of hibernation/dual boot method, currently, but it would take a lot of programming skill to work.

Last evening my j720 had a fully charged battery (it is a good but not new standard j720 battery). I pushed on/off in NetBSD, and when I checked it 9 hours later using the HP settings tool, it was missing only one bar. Especially given the way the battery meter works, it might last a few days or more...

I am using the kernel found at: ftp://ftp.netbsd.org/pub/NetBSD/misc/peter/hpcarm/netbsd along with the daily hpcarm builds. The current kernel build seems to freeze after setting up the CF drive, although apparently it is related to the keyboard driver.

Does this hibernation/dual boot method you speak of involve something like writing to CF the contents of the Windows CE RAM (setup to autorun the bootloader), and then restoring the RAM on BSD shutdown so that CE doesn't hard reset? I thought of that yesterday, but I just got this device and don't know much about its internal workings yet.

Edited by isotherm 2006-05-28 11:46 AM

Yeah, that is pretty much the idea, much easier said than done. As far as the power, that is a rather long time to only lose one bar. Perhaps their suspend cuts off more of the 720 than ours does, because I can run programs when Linux is "suspended". Is your battery refurbished?

The NetBSD suspend is quite a bit better than the Linux suspend. I don't know what they do, exactly. But if you want to take advantage of CE's sleep you can push soft reset and then suspend it. Can't do that with Linux last I knew, without taking out both batteries.

I don't really know the condition of the battery, but I think it's the one that originally came with the unit. It lasts about 6 hours with cellular in CE.

Edited by isotherm 2006-05-30 5:05 PM

Yeah, I should check it out. I bet that they figured out how to power down more parts of the device. I would be fine with that. Anyways, soft reset for suspend is impossible, at least currently...the device wakes up into CE rom, but the ram is not cleared yet. So it crashes.