PowerManagementConfiguration

Differences between revisions 31 and 41 (spanning 10 versions)
⇤ ← Revision 31 as of 2005-11-19 07:36:03 →
Size: 6927
Editor: tvwna-ip-a-1
Comment: + mockups
← Revision 41 as of 2006-02-23 11:15:25 → ⇥
Size: 7168
Editor: haddenham
Comment: Tidy the specification to make it more reflect reality for dapper
Deletions are marked like this. Additions are marked like this.
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 * '''Created:''' [[Date(2005-04-23T01:36:42Z)]] by MattZimmerman
 * '''Contributors:''' MatthewGarrett, OliverGrawert, MatthewPaulThomas, ThomMay, ReinhardTartler, RyanLortie, CoreyBurger, MatthiasUrlichs, MartijnVanDeStreek, DanielHolbach
 * '''Drafter:''' DanielHolbach
 * '''Assignee:''' RyanLortie
 * '''Packages:''' `gnome-power`, `gnome-session`, `gnome-applets`		  * '''Created:''' [[Date(2005-04-23T01:36:42Z)]] by MattZimmerman, replaced [[[Date(2006-02-23T11:15:25Z)]]] by DanielSilverstone
 * '''Original Contributors:''' MatthewGarrett, OliverGrawert, MatthewPaulThomas, ThomMay, ReinhardTartler, RyanLortie, CoreyBurger, MatthiasUrlichs, MartijnVanDeStreek, DanielHolbach
 * '''Original Drafter:''' DanielHolbach
 * '''Original Assignee:''' RyanLortie
 * '''Original Packages:''' `gnome-power`, `gnome-session`, `gnome-applets`
 * '''Drafter:''' DanielSilverstone
 * '''Assignee:''' DanielSilverstone
 * '''Packages:''' `gnome-power-manager`, `gnome-session`, `control-center`, `hal`
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GNOME Power Preferences should by default only propose controversial options (ie: if we suspend when the lid closes). Other options have sane defaults which we should select for the user and not ask them about. For example, the following events are assumed to behave as follows:
 * power button press -> logout dialog
 * suspend press (if exists) -> suspend
 * ac unplugged -> so what? (do nothing -- but go into laptop mode!)		 To maintain simplicity, Ubuntu's power management interface allows configuration only of those options that people are likely to want to change (with other options having sane defaults, not configurable graphically). We will present battery and power information for the computer itself and also any other battery-powered devices which hal can tell us about.
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== Use Cases == == Use cases ==
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 * Mei-li is flying back to her home in London after a successful business trip to Hong Kong (during which she persuaded Michael to install Ubuntu). She does as much work as she can on her ThinkPad during the flight, with Ubuntu automatically putting the machine into hibernation when the battery reaches a critically low level. Nineteen hours later, Mei-li arrives back at her apartment, plugs in her ThinkPad, opens it up and resumes work from where she left off.  * Mei-Li is flying back to her home in London after a successful business trip to Hong Kong (during which she persuaded Michael to install Ubuntu). At the start of the flight, she sees she has 3 hours 20 minutes of battery left on her Think``Pad, possibly enough to finish a presentation she has to give tomorrow. As it turns out, she doesn't quite finish it; Ubuntu automatically puts the machine into hibernation when the battery reaches a critically low level. Nineteen hours later, Mei-Li arrives back at her apartment, plugs in her Think``Pad, opens it up and resumes work from where she left off.
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 * Candice runs a university computer lab containing 60 iMacs -- a significant use of electricity for a university on a tight budget (they upgraded from Mac OS 9 to Ubuntu partly because it was cheaper than OS X). To save power, Candice wants each computer to go to sleep if idle for half an hour, and she does not want students to be able to alter the power management settings.  * Candice runs a university computer lab containing 60 iMacs -- a significant use of electricity for a university on a tight budget (they upgraded from Mac OS 9 to Ubuntu partly because it was cheaper than OS X). To save power, Candice wants each computer to go to sleep if idle for half an hour, even when nobody is logged in, and she does not want students to be able to alter the power management settings.
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=== Panel Icon === === Power Manager Interface ===
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There will be exactly one power status icon on the panel (either applet or notification icon), which will show the current battery charge status. The icon will only show "primary" battery status (we make no attempt to deal with wireless mouse batteries, for example). The icon will not have its own preference dialog, but rather, a pulldown menu. The preferences item in this menu will lead to the global power preferences dialog (same dialog that is accessed via the System -> Preferences menu).

attachment:power-menu.jpg

(NB: RyanLortie is currently working on this patch for battstat-applet)		 The `gnome-power-manager` package provides us with a notification-area icon which displays information about the battery status. It should be possible to get it to provide a popup of the current status on a given keypress (many laptops have a battery key which would be ideal for this).
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attachment:shutdown.jpg Pressing the power button on the computer puts up the shutdown alert immediately.
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 * Power button -> pop up the power off dialog
 * dialog box must be there -very- fast. don't do fading screen effect if we can't do it quickly (NB: gnome logout dialog does it slow but gnome-screensaver can do it quickly. find out why.)
 * all options in dialog are accessible with single (no need to hold alt) keypress.
 * default is poweroff, accessible by pressing enter
 * button order is important here. this is according to the gnome HIG. the only negotiable items are the restart and sleep buttons.		 The Alert provides for shutting down the computer, rebooting it, putting it to sleep, etc.
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=== Power Preferences Dialog === === Power Management preferences ===
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attachment:power-applet.jpg By using the gnome-power-manager preferences applet we reduce the development work needed at the expense of one or two of our use-cases being incomplete. In particular, Candace's iMacs won't sleep when noone is logged in and Courtney will still be at the mercy of her malicious sister.
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 * if suspend is unsupported then:
   - hide suspend time slider
   - hide suspend-on-lid-close option
 * time until automatic suspend
 * checkbox for suspend on lid close
   - defaults to on if suspend is whitelisted for laptop
 * checkbox for "require password when waking from sleep/hibernate"
   - defaults to off if user is autologin
   - essentially, invoke the screensaver just before suspending
 * sliders for battery low in TIME (not percentage)
   - warnings issued for battery low
   - automatic shutdown for battery critical
     - automatic shutdown may be disabled by hidden gconf key
 * we intentionally don't consider, for example, putting the computer to sleep when on AC.
 * the lock-on-sleep option has no effect on the normal behaviour of the screensaver.		 == Implementation ==
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== Implementation Plan == For Ubuntu, `gnome-power-manager` will be used. With a small amount of work, this should be suitable for Xubuntu - KDE already has a runtime configuration system. The `gnome-power-manager` package provides us with almost all of the functionality we desire. Where it diverges from our requirements, it is likely that it simply hasn't tried to address those points yet. I anticipate a reasonably large diff between upstream and Ubuntu in the first instance.
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In its current state, gnome-power-manager is insufficient for our purposes. The primary problem is that it runs as a gnome session daemon. This causes three problems:
 * Kubuntu and Xubuntu get no love
 * power management doesn't work when at the login screen
 * security issues are introduced if any user (logged in or not) can ask the system to immediately suspend (as is the current case with g-p-m).		 A small amount of work is required for this to be possible:
 * Investigation into providing policy when no user is logged in, and changing to system policy when the user logs in/out (RichardHughes is working on this upstream although I don't currently believe it'll be ready in time.)
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The plan is to attempt to work with upstream to address these changes. Specifically, we have asked the following:
 * We require a system policy daemon running as root.
 * Users in group power-config will be able to change power config without password.
 * Users not in this group are prevented from modifying the settings.
 * Use dbus to talk to system daemon, which will make certain they are in the right group.
 * We prefer to have each user able to specify their own settings.
 * If each user can set their own settings then there must be a clear way to set defaults (for new users, login screen) possibly only accessible to admin user.
 * If each user can set their own settings then the new settings must be activated when the user logs in and the default settings must be restored on user logout.		 === Further details ===
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If upstream is willing to work with us then gnome-power-manager will be shipped. If we can't get gnome-power-manager into an acceptable state on time then we will fall back on the default action of continuing with our current power management scripts with a configuration interface added on. dbus has had the at_console policy patched to check that the user is at the foreground console. This requires libpam-foreground to be part of the default pam session. This is the case as of current dapper.
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This way only the 'active' user can do power management stuff but it doesn't address the issue of preventing certain users from messing with power settings. However we believe this is an acceptable situation for the first pass (the best you could do is prevent any power management stuff from occuring when a certain user is logged in).

attachment:diagram.png

== Future work ==

 * Find a less bad way of expressing the relationship between computer sleep and display sleep.
 * Find a less confusing way of allowing lockdown of non-admin accounts.
 * Allow configuration of UPS devices.
RichardHughes: g-p-m already detects UPS's using HAL. At the moment only APC UPS's are supported, but it's pretty trivial to convert a NUT plugin to a HAL addon for other makes. g-p-m treats them like external batteries, doing the usual (hibernate/shutdown etc) when they get critical, with warnings when they get low. What else would you want to configure, other than the time before shutting down?
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 * How do we cater for Bob's use case?
 * How do we cater for Courtney's use case?		  * How do we cater for the part of Candice's use case where she wants to configure what happens while nobody is logged in?
RichardHughes: I was proposing using the root user preferences, i.e. safe defaults.

== Proposals outside of the specification's remit ==

 * NicolòChieffo: a way to switch between different power configurations (for laptops) should be a good feature too. Last month I made a simple script using zenity, to support this (it's called power4gear because my laptop has a hotkey called power4gear). to let you know what I'm talking about I'll give you the [http://bugzilla.ubuntu.com/show_bug.cgi?id=17652 link] (there is also a screenshot in the .tar.gz). Let me know

----
CategorySpec

Summary

To maintain simplicity, Ubuntu's power management interface allows configuration only of those options that people are likely to want to change (with other options having sane defaults, not configurable graphically). We will present battery and power information for the computer itself and also any other battery-powered devices which hal can tell us about.

Rationale

There should be simple, reliable, and understandable methods of:

  • shutting down the computer
  • putting the computer into a low-power-use state
  • going into a low-power-use state after some period of inactivity
  • blanking the screen, instead of using a power-sapping screensaver, when running on battery power
  • preventing data loss when the battery runs out.

Currently people need to edit text files in /etc to enable suspend to RAM, and to select which services will be restarted. Also, it's currently impossible to configure how the system should behave in various situations, such as on lid close. All of these points should be configurable graphically.

Use cases

  • Michael is a harried Hong Kong businessman who has just installed Ubuntu 6.04 on his home desktop machine. He doesn't care about power management; he wants it to just work and do the right thing.

  • Mei-Li is flying back to her home in London after a successful business trip to Hong Kong (during which she persuaded Michael to install Ubuntu). At the start of the flight, she sees she has 3 hours 20 minutes of battery left on her ThinkPad, possibly enough to finish a presentation she has to give tomorrow. As it turns out, she doesn't quite finish it; Ubuntu automatically puts the machine into hibernation when the battery reaches a critically low level. Nineteen hours later, Mei-Li arrives back at her apartment, plugs in her ThinkPad, opens it up and resumes work from where she left off.

  • Candice runs a university computer lab containing 60 iMacs -- a significant use of electricity for a university on a tight budget (they upgraded from Mac OS 9 to Ubuntu partly because it was cheaper than OS X). To save power, Candice wants each computer to go to sleep if idle for half an hour, even when nobody is logged in, and she does not want students to be able to alter the power management settings.
  • Bob runs the IT department at Hydroponical Light Industries. He gives his salespeople laptops with Ubuntu preinstalled, but since they're salespeople and not tech wizards, Bob locks down the power settings so they can't be messed with.
  • Courtney shares her Presario with her evil twin sister, Tara. Tara likes playing practical jokes, and tries to set up a cron job to spontaneously shut down or suspend the system if Courtney is logged in. This is unsuccessful.

Design

Power Manager Interface

The gnome-power-manager package provides us with a notification-area icon which displays information about the battery status. It should be possible to get it to provide a popup of the current status on a given keypress (many laptops have a battery key which would be ideal for this).

Shutdown confirmation alert

Pressing the power button on the computer puts up the shutdown alert immediately.

The Alert provides for shutting down the computer, rebooting it, putting it to sleep, etc.

Power Management preferences

By using the gnome-power-manager preferences applet we reduce the development work needed at the expense of one or two of our use-cases being incomplete. In particular, Candace's iMacs won't sleep when noone is logged in and Courtney will still be at the mercy of her malicious sister.

Implementation

For Ubuntu, gnome-power-manager will be used. With a small amount of work, this should be suitable for Xubuntu - KDE already has a runtime configuration system. The gnome-power-manager package provides us with almost all of the functionality we desire. Where it diverges from our requirements, it is likely that it simply hasn't tried to address those points yet. I anticipate a reasonably large diff between upstream and Ubuntu in the first instance.

A small amount of work is required for this to be possible:

  • Investigation into providing policy when no user is logged in, and changing to system policy when the user logs in/out (RichardHughes is working on this upstream although I don't currently believe it'll be ready in time.)

Further details

dbus has had the at_console policy patched to check that the user is at the foreground console. This requires libpam-foreground to be part of the default pam session. This is the case as of current dapper.

This way only the 'active' user can do power management stuff but it doesn't address the issue of preventing certain users from messing with power settings. However we believe this is an acceptable situation for the first pass (the best you could do is prevent any power management stuff from occuring when a certain user is logged in).

attachment:diagram.png

Future work

  • Find a less bad way of expressing the relationship between computer sleep and display sleep.
  • Find a less confusing way of allowing lockdown of non-admin accounts.
  • Allow configuration of UPS devices.

RichardHughes: g-p-m already detects UPS's using HAL. At the moment only APC UPS's are supported, but it's pretty trivial to convert a NUT plugin to a HAL addon for other makes. g-p-m treats them like external batteries, doing the usual (hibernate/shutdown etc) when they get critical, with warnings when they get low. What else would you want to configure, other than the time before shutting down?

Outstanding issues

  • How do we cater for the part of Candice's use case where she wants to configure what happens while nobody is logged in?

RichardHughes: I was proposing using the root user preferences, i.e. safe defaults.

Proposals outside of the specification's remit

  • NicolòChieffo: a way to switch between different power configurations (for laptops) should be a good feature too. Last month I made a simple script using zenity, to support this (it's called power4gear because my laptop has a hotkey called power4gear). to let you know what I'm talking about I'll give you the [http://bugzilla.ubuntu.com/show_bug.cgi?id=17652 link] (there is also a screenshot in the .tar.gz). Let me know

CategorySpec

PowerManagementConfiguration (last edited 2008-08-06 16:31:02 by localhost)