Handbrake somehow inhibiting display standby?

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mod16
Posts: 76
Joined: Sun Jan 12, 2014 11:10 am

Handbrake somehow inhibiting display standby?

Post by mod16 » Fri Aug 11, 2017 6:19 pm

I know this is a weird question, but it's also a strange issue. It may also not be related to Handbrake at all.

I'm using KDE on Manjaro Linux. I'm building Handbrake from source.

In KDE, I've set the display/monitor standby to 20 minutes - and I'm having the issue, that sometimes the display just doesn't turn off as it should be. After a while I realized, that this issue occurs only when the Handbrake GUI is open and encoding. The display does turn off (after the idle time) if the GUI is only open but no job is running. So far Handbrake seems to be the only application having this influence on the standby mode.

Now if I run "xset -q" while Handbrake GUI is open but idle, I get:

Code: Select all

$ xset -q
[...]
DPMS (Energy Star):
  Standby: 1200    Suspend: 1800    Off: 2400
  DPMS is Enabled
  Monitor is On
But as soon as a job is running, it get:

Code: Select all

$ xset -q
[...]
DPMS (Energy Star):
  Standby: 0    Suspend: 0    Off: 0
  DPMS is Disabled
If I stop encoding or the queue finishes, I get the output above again (DPMS enabled).

So I'm not sure where to look next!? Why is it doing this? Any ideas?

The only idea I have for now is to test other CPU intensive programs, if they produce the same result. But still I would have no idea why? I really can't imagine an OS or DE "feature" that disables display standby if there is a high CPU load. :wink: :D

Just wanted to ask here if anyone maybe had the same issue?

User avatar
JohnAStebbins
HandBrake Team
Posts: 5007
Joined: Sat Feb 09, 2008 7:21 pm

Re: Handbrake somehow inhibiting display standby?

Post by JohnAStebbins » Mon Aug 14, 2017 5:08 pm

The HandBrake GUI tries 2 dbus interfaces to request that power management be suspended during encoding. First it tries org.gnome.SessionManager, then it tries org.freedesktop.PowerManagement. Neither of these interfaces are very well documented which is frustrating (I guess you get what you pay for :mrgreen:). This should only be disabling session and computer suspend functions. As far as I understand, this shouldn't affect screen locks or display power settings. But the documentation on these interfaces is not terribly clear (in fact it's pretty much non-existent).

I haven't received any other reports of the screen power settings being modified, but I'll do a little digging to see if I can find out more.

mod16
Posts: 76
Joined: Sun Jan 12, 2014 11:10 am

Re: Handbrake somehow inhibiting display standby?

Post by mod16 » Thu Aug 17, 2017 9:36 am

Thank you for your reply and additional information! At least the behavior makes some sense now. :)

If you need more information on used Kernel, libs etc. I'm happy to provide it.

If I myself find any useful "discoveries" I will also report back here.

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