Slashdot Mirror

← Back to Stories (view on slashdot.org)

OpenBSD Gains Centrino Power Management

Posted by michael on from the save-a-watt-or-two dept.

In a recent email, Theo de Raadt announced support in -current for power management on the Pentium M series of processors. This allows the CPU to be throttled and therefore power saved. Additionally, dhclient was modified so that it is not necessary to find the process of the already-running dhclient and kill it before running dhclient again. This is useful for laptops that spend time roaming between different wireless networks, when dhclient is used fairly often.

17 of 49 comments (clear)

  1. Before anyone comments, on linux it's cpufreq by Ayanami+Rei · · Score: 3, Informative

    And yes, it supports Centrino.

    --
    THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
    1. Re:Before anyone comments, on linux it's cpufreq by Anonymous Coward · · Score: 3, Interesting

      A little offtopic maybe, but I've always been curious... One of the things I love the most about my PowerBook is how it wakes up immediately when I open the cover, in contrast to my friend's Dell laptop (running Windows XP) that takes forever to wake up from hibernate. How long does it take for a Linux system with Gnome or KDE to wake up from sleep and be usable?

      I have no firsthand experience in this area so I'd be interested to know. Thanks...

  2. In fact, the only OS that doesn't have a native by Ayanami+Rei · · Score: 3, Informative

    interface now seems to be Windows NT 5.x. (okay, so XP SP1 supports automatic throttling, but you can't control it)
    Yawn. 3rd party software? Bleah.

    --
    THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
  3. If it's hibernating, it won't be any faster. by Ayanami+Rei · · Score: 2, Informative

    But if it was just asleep, it takes about 3 or 4 seconds to be usable (that's about how long it takes to intialize the video and spin up the hard drive if necessary).

    It seems about consistent for linux and windows. I imagine FreeBSD is the same; I've never used it on a laptop.

    --
    THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
    1. Re:If it's hibernating, it won't be any faster. by Anonymous Coward · · Score: 2, Interesting

      Thanks for your informative reply. I didn't know there was a difference between hibernate and sleep. I googled around a bit and found this explanation. However, it seems that in sleep mode the battery will only last a day or two (on a Dell laptop, at least), and that's just unacceptable--my PowerBook lasts a week or more. I imagine this has more to do with the hardware than the software, however, so I guess the only way to find out how long it would take for my PowerBook to wake up from sleep under Linux and BSD would be to just try it myself. Perhaps I'll get around to it someday. :)

    2. Re:If it's hibernating, it won't be any faster. by addaon · · Score: 3, Informative

      Yup, there are three differences between the powerbooks and (most, not all) pc laptops. First, the powerbooks are energy-star compliant, which is a goofy way of saying they draw 1W of power when suspended (on battery; they actually take about 3W when on AC, for reasons I don't quite get). This is what allows such long suspend times. Second, they don't support hibernate at all; if you're going away for vacation for a month or more, you have no choice really but to either plug in the powerbook, or shut it down; with a pc, you'd probably just hibernate it. Third, the lid switches work really damn well. There are a lot of PC's that have that, now, but it's still not consistent... the goal, just to let the pc makers know, is so that closing suspends immediately, and opening has an image on the screen before the screen is visible to the user.

      --

      I've had this sig for three days.
    3. Re:If it's hibernating, it won't be any faster. by dvmiller · · Score: 2, Informative

      (on battery; they actually take about 3W when on AC, for reasons I don't quite get)

      It's charging the battery as well when it's on AC power.
  4. OpenBSD and Laptops by Sloppy · · Score: 3, Interesting
    Anyone have any recommendations for a laptop, for which the built-in stuff (particularly wireless interfaces) is supported by OpenBSD?

    I don't care much about processor speed or fancy video (as long as XFree86 works with it). Just need to run a web browser and an IMAP client.

    I think this OS might be a good choice for laptops, since those tend to get connected to hostile networks without a friendly firewall between me and "them."

    I would also want an encrypted /home, at a minimum, since lightweight computers are more vulnerable to loss/theft than typical desktops. (And my home dir would contain config files for my IMAP client, which would contain authentication info.) OpenBSD can do that, right?

    --
    As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
    1. Re:OpenBSD and Laptops by lcde · · Score: 2, Informative

      I've run 3.2 and now 3.4 on my Compaq E500 Armada. Everything seems to be supported without any problems. I also have a Dlink DWL-650 wireless card.

      --
      :%s/teh/the/g
    2. Re:OpenBSD and Laptops by damian.gerow · · Score: 4, Interesting

      Have you looked into FreeBSD? 5.x is coming along {nicely,horribly}, and has GEOM, CPU throttling, ACPI, and pretty extensive hardware support. It's also got a more modern compiler, which has caused some small issues with OpenBSD (namely, PowerDNS won't compile and/or run).

      Don't get me wrong -- OpenBSD definitely has its place, but it's possible to secure /any/ OS. And these changes to dhclient most certainly /would/ be welcome. But I know that FreeBSD has native support for low-level encryption, and that seems to be pretty important for laptops. I also find FreeBSD makes a better desktop, but that's a matter of personal choice.

    3. Re:OpenBSD and Laptops by jschauma · · Score: 3, Interesting

      Dunno 'bout OpenBSD, but NetBSD will certainly be a good choice, too. See this page for some reports of NetBSD on laptops.

      As for encrypted /home, take a look at NetBSD's cryptographic disk driver. I use it on my IBM T30 to encrypt /home and swap. Neato.

      --

      -- "Tradition is the illusion of permanence."
    4. Re:OpenBSD and Laptops by Brandybuck · · Score: 2, Informative

      Don't know about OpenBSD, but FreeBSD-5.2 runs just fine on my Compaq Presario 2591. Everything but the winmodem worked out-of-the-box. I've never used it, but the FreeBSD GEOM system supports an encrypted filesystem.

      --
      Don't blame me, I didn't vote for either of them!
    5. Re:OpenBSD and Laptops by Anonymous Coward · · Score: 2, Informative
      check out openbsd-mobile@monkey.org

      i highly recommend IBM Thinkpads, in particular the X series (very portable). OpenBSD runs like a charm on most thinkpads -- many OpenBSD developers use thinkpads, so you know that the video card, etc will work ;)

    6. Re:OpenBSD and Laptops by SteelX · · Score: 2, Informative

      Not sure if it's helpful, but I run OpenBSD on a Dell Latitude L400 (yes, it's old). Most things work, except the sound toggle buttons (I can't increase/decrease the volume via the keyboard's Fn+{F5,F6} buttons).

      If all you need is XFree86, a web browser, and IMAP client, I highly recommend OpenBSD. OpenBSD is more than sufficient. You can make a really slick desktop with it, but it does take more time to set up than Linux or possibly FreeBSD. However, you'll learn heaps as you go along.

      Disclosure: I'm also a Slackware user, and absolutely love tinkering with stuff and learning the internals of systems. :) That may be the reason why I don't mind all the tinkering that goes into getting a beautiful OpenBSD desktop up and running. That might put other people off, though. YMMV.

  5. Re:The Straight Dope by 101percent · · Score: 3, Funny

    Netcraft runs on FreeBSD!

  6. Linux and Pentium-M by lonesometrainer · · Score: 3, Interesting

    I don't know. 3 months age we bought 4 Thinkpads T40p, mainly because of the incredible batterie times everyone seemed to be experiencing with these machines. Kernel 2.6+ACPI+cpufreq+some tricks from several mailing lists give us max. 3h with display set to darkest level and bios settings to max battery life.

    Windows may not be able to fine-control the machine as much as you can with the upper configuration, but a xp-test-installation kept the machine up and running for nearly 5 hours (nearly same work on the machine...).

    Any tips from Linux Pentium-M experts???

  7. That is good! by Anonymous Coward · · Score: 2, Funny

    daniel parsons has no wang.

    Good for him. Wang hasn't been a computer maker anyone has bothered to care about for years.

    The only reason to hold onto a wang at this point is nostalaga and a high electric bill to keep it powered.