Difference between revisions of "Talk:Laptop"

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m (RUN+="" won't work reliably: oops...)
m (System76: rw)
 
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==Udev Rule to Suspend System==
 
The udev rule could be edited to run a script that does polls the battery's capacity at regular interval when it's status changes to Discharging:
 
## SLEEP IF BATTERY IS LOW
 
SUBSYSTEM=="power_supply", ATTR{status}=="Discharging", <s>ATTR{capacity}=="2", RUN+="/usr/bin/systemctl suspend</s> RUN+="/script/to/poll/battery/and/suspend/system.sh"
 
There may also be a uevent that fires when the battery reaches an alarm state (when /sys/class/power_supply/BAT*/alarm is reached or changes).  I have not tested this on my own system yet or figured out just how that file works yet. [[User:Ego.abyssi|Ego.abyssi]] ([[User talk:Ego.abyssi|talk]]) 23:32, 3 March 2013 (UTC)
 
 
:Strange, on my system battery sends "change" uevent each time battery is charged or discharged by 1%, so rule works perfectly and polling is an overcomplication.
 
:--[[User:Eruditorum|Eruditorum]] ([[User talk:Eruditorum|talk]]) 06:48, 30 March 2013 (UTC)
 
 
::Hmm...  Well, if it works for you, then it must be something peculiar with my specific system.  In which case, yes, polling would be a needless complication.  I'll have to give it a look and see what the dillyo is. [[User:Ego.abyssi|Ego.abyssi]] ([[User talk:Ego.abyssi|talk]]) 05:58, 16 May 2013 (UTC)
 
 
:::On my system, acpi sends only adapter online/offline events, no ''changed-battery-level'', so the only solution is a daemon polling the battery level every minute or so... -- [[User:Lahwaacz|Lahwaacz]] ([[User talk:Lahwaacz|talk]]) 16:42, 6 June 2013 (UTC)
 
 
 
== RUN+="<command>" won't work reliably ==
 
== RUN+="<command>" won't work reliably ==
  
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:The {{ic|1=ENV{SYSTEMD_WANTS}="suspend.target"}} should be used ideally, but it has to be combined with {{ic|1=TAG+="systemd"}}.
 
:The {{ic|1=ENV{SYSTEMD_WANTS}="suspend.target"}} should be used ideally, but it has to be combined with {{ic|1=TAG+="systemd"}}.
 
:-- [[User:Lahwaacz|Lahwaacz]] ([[User talk:Lahwaacz|talk]]) 19:38, 26 September 2013 (UTC)
 
:-- [[User:Lahwaacz|Lahwaacz]] ([[User talk:Lahwaacz|talk]]) 19:38, 26 September 2013 (UTC)
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::Isn't the point that systemctl may not finish executing - certainly may not finish quickly enough for udev's liking? It is a matter of what is suitable in a udev rule due to the nature of udev. --[[User:Margali|cfr]] ([[User talk:Margali|talk]]) 01:47, 8 November 2013 (UTC)
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== systemd-tmpfiles ==
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Re [https://wiki.archlinux.org/index.php?title=Laptop&diff=447520&oldid=447470], how is this any different from other tmpfiles entries? -- [[User:Alad|Alad]] ([[User talk:Alad|talk]]) 10:51, 23 August 2016 (UTC)
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:For example in [[Maximizing_performance#systemd-tmpfiles]] you're writing the desired value to the "special" file, but here you're just toggling the state for the event you write to the file. It would work assuming that systemd-tmpfiles is run just once after boot, but that's not the case. -- [[User:Lahwaacz|Lahwaacz]] ([[User talk:Lahwaacz|talk]]) 11:05, 23 August 2016 (UTC)
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== <s>System76</s> ==
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I think this should cover System76 and probably ZaReason as well. [[User:Ben Creasy|Ben Creasy]] ([[User talk:Ben Creasy|talk]]) 04:44, 29 November 2016 (UTC)
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:Considering the low market share and that we don't even have pages for those laptop brands, "Other" is good enough. -- [[User:Alad|Alad]] ([[User talk:Alad|talk]]) 06:30, 29 November 2016 (UTC)

Latest revision as of 06:30, 29 November 2016

RUN+="<command>" won't work reliably

In the example:

/etc/udev/rules.d/lowbat.rules
# Suspend the system when battery level drops to 2%
SUBSYSTEM=="power_supply", ATTR{status}=="Discharging", ATTR{capacity}=="2", RUN+="/usr/bin/systemctl suspend"
RUN
...
Starting daemons or other long running processes is not appropriate for
udev; the forked processes, detached or not, will be unconditionally killed
after the event handling has finished.

There's no garantee that systemctl will finish execution. Its possible to use ENV{SYSTEMD_WANTS}="systemd-suspend.service" but I have not personally tested this. All these udev rules should be reworked to trigger one-shot systemd services ideally, which also brings along all the benefits of have systemd units (logging, debugging, etc).

-- Simongmzlj

First of all, RUN+= is not deprecated. Missing features do not predicate deprecation. I've removed the accuracy note from the page: [1].
The ENV{SYSTEMD_WANTS}="suspend.target" should be used ideally, but it has to be combined with TAG+="systemd".
-- Lahwaacz (talk) 19:38, 26 September 2013 (UTC)
Isn't the point that systemctl may not finish executing - certainly may not finish quickly enough for udev's liking? It is a matter of what is suitable in a udev rule due to the nature of udev. --cfr (talk) 01:47, 8 November 2013 (UTC)

systemd-tmpfiles

Re [2], how is this any different from other tmpfiles entries? -- Alad (talk) 10:51, 23 August 2016 (UTC)

For example in Maximizing_performance#systemd-tmpfiles you're writing the desired value to the "special" file, but here you're just toggling the state for the event you write to the file. It would work assuming that systemd-tmpfiles is run just once after boot, but that's not the case. -- Lahwaacz (talk) 11:05, 23 August 2016 (UTC)

System76

I think this should cover System76 and probably ZaReason as well. Ben Creasy (talk) 04:44, 29 November 2016 (UTC)

Considering the low market share and that we don't even have pages for those laptop brands, "Other" is good enough. -- Alad (talk) 06:30, 29 November 2016 (UTC)