enabling more kpowersave options

Discussion in 'Linux' started by nataku, Sep 2, 2008.

  1. nataku

    nataku

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    I've been searching all around and from what I see, kpowersave should have the options to suspend to ram or suspend to disk. I want to enable these options so when I close the lid, it saves to disk. That way, it does not use up much or almost any power when it's closed, vs standby which slowly drains it.

    I can't find a configuration file for kpowersave. Does anybody know where that's stored and if that's where I'll be able to set these options, or enable them in the GUI? I'm not sure why it wouldn't be enabled before, as they're useful options that look like they normally come with kpowersave installed.

    Thanks
     
    nataku, Sep 2, 2008
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  2. nataku

    annafil

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    Ok first of all, the reason suspend to disk (hibernate) is not enabled on the aspire one is because of the SD storage expansion - there are known issues with hibernating and the risk of data loss, so I don't recommend that.

    Secondly, there isn't a good way to get kpowersave to see more options (I tried getting non-acer kpowersave packages and no go).

    But there is another way. You can replace kpowersave with the gnome-power-manager. You will need to resolve some dependency problems as explained by macles.blogspot.com in a recent post, then install the package and make sure kpowersave isn't auto-starting at bootup any more.

    I'm planning on putting up a howto in the next couple of days, because it's not as straightforward as it seems. The suspend script, for instance, is different under gnome-power-manager and so you need to tell GPM not to use those and tweak the default acpi suspend. It's a mess :)

    If you feel up for it on your own, have fun, and maybe post your experiences - it would help in writing the howto.
     
    annafil, Sep 2, 2008
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  3. nataku

    joaer

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    Is the save to disk feature enabled in the kernel config? Given the lack of other features in the AA1 version of the kernel, I find that plausible. ( I haven't access to the AA1 .config-file right now so I cannot check.)

    Besides, suspend to disk means writing half a gigabyte to solid state disk, which due to the nature of SSDs is slow and also wears it out. So I suspect that Acer deliberately cut that feature out. Understandable but sad because I like the concept; on Windows I almost always go into hibernation when I'm done.

    EDIT: annafil, you beat me with a minute. :) So if I understand you right, as long as I don't have any SD expansion, it is pretty safe to suspend to disk? (Not taking into account the additional wear on the SSD.)
     
    joaer, Sep 2, 2008
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  4. nataku

    annafil

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    joaer: I wouldn't go as far as to say it's very safe. Like you said - there's still a lot of wear on the SSD by using hibernate.

    Also, you're right in that hibernation will be far slower than shutting down and rebooting or using suspend.

    I'm not sure there's a lot that hibernation does that can't be achieved with what you already have. Presumably you want to hibernate and save your apps the way they are running while putting the pc to a state where it uses almost no power? In that case, you could use a session saver to accomplish the same thing on shutdown. Unfortunately, the acer modified xfce4 packages have a broken session-saver :(
     
    annafil, Sep 2, 2008
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  5. nataku

    nataku

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    odd, with an ssd, you'd think it would be more robust in terms of being able to write and re-write data to the disk.

    Your explanations make sense though. I'll have to look into the session manager or gnome-power-manager as well. Question though, gnome-power-manager obviously denotes it's from gnome interface; can these be used interchangeably with xfce, or kde for that matter?
     
    nataku, Sep 3, 2008
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  6. nataku

    rjm

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    hibernate prolly isnt enabled 'cus its faster to reboot than it is to reload the memory contents....
     
    rjm, Sep 3, 2008
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  7. nataku

    Colt45

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    When I check Power Center, my settings are always "Balanced". I want to set it to Performance on AC and Power Saver on the battery. I've made the change several times, but it always comes back as "Balanced". How do I force this change and make it stay?
     
    Colt45, Sep 3, 2008
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  8. nataku

    annafil

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    colt45: the short answer is, you can't make it stick with kpowersave, but you can with gnome power manager

    im writing the howto I just need to figure out one last thing before putting it up
     
    annafil, Sep 3, 2008
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  9. nataku

    joaer

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    The reason is that solid state disks are built up using FLASH memory, which has an upper limit on the number of erases that can be done (http://en.wikipedia.org/wiki/Flash_memory#Memory_wear). The more you write/erase, the faster you wear it out. Now, usually it is no problem (we are talking about several thousands of erases) but if you write/erase 512 out of 8192 Mbytes every time you hibernate, it will add up.
     
    joaer, Sep 3, 2008
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  10. nataku

    nataku

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    thanks for the explanation joaer, that makes sense
     
    nataku, Sep 4, 2008
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