Locking from user menu fails second time (gnome-screensaver SimulateUserActivity() doesn't return)

Actually appears something is hanging around after unlocking, that blocks indicator session for a bit. If you wait a few minutes between unlock and locking again (or log-out etc), the lock screen appears without delay.

Status changed to 'Confirmed' because the bug affects multiple users.

Don't think this is a bug in indicator-session. Basically indicator-session is just calling two dbus methods on org.gnome.ScreenSaver; Lock and SimulateUserActivity. It seems that the SimulateUserActivity call is not returning immediately. I can illustrate this with a simple script:

#!/bin/bash

dbus-send --session --print-reply --dest=org.gnome.ScreenSaver \
  /org/gnome/ScreenSaver org.gnome.ScreenSaver.Lock
dbus-send --session --print-reply --dest=org.gnome.ScreenSaver \
  /org/gnome/ScreenSaver org.gnome.ScreenSaver.SimulateUserActivity

which when run, locks the screen and then shows the lock screen immediately. When you unlock the screen, the script will still be blocked until the timeout is reached, where we get:

method return sender=:1.79 -> dest=:1.103 reply_serial=2
Error org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.

The first line is from the successful call to Lock. The call to SimulateUserActivity is also successful since the lock screen appears immediately, but we never get a reply.

A decent workaround might be to set the timeout to some low value, say 1 second. It seems to work when setting --reply-timeout=1 in the script, I'm going to try rebuilding indicator-session with that value and see if it helps (though I am curious why we never get a reply).

Seems to fix it here, attaching a debdiff with the workaround. Curious if this is due to some change in dbus, I know quantal included at least the eavesdropping changes (though I would think we should be able to get the reply to our own method call).

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Thanks for the debugging Jason, I wonder if that makes it a gnome-screensaver bug then, it seems like SimulateUserActivity should give a reply...

interesting, calling SimulateUserActivity() in d-feet leads to block the ui as well, really looking like a gnome-screensaver issue...

Ok, looking a bit to it, doing:

dbus-send --session --print-reply --dest=org.gnome.ScreenSaver /org/gnome/ScreenSaver org.gnome.ScreenSaver.SimulateUserActivity

blocks on the current code

The patch there "fixes" the issue, I'm not sure it's right though, I would appreciate comments of people knowing that code better than me :-)

Ok, after IRC discussion that seems right, I've forward to https://bugzilla.gnome.org/show_bug.cgi?id=686400 and will upload

Hello Tim, or anyone else affected,

Accepted gnome-screensaver into quantal-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/gnome-screensaver/3.6.0-0ubuntu2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please change the bug tag from verification-needed to verification-done. If it does not, change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Tested with package from -proposed, this issue is now resolved!

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.

This bug was fixed in the package gnome-screensaver - 3.6.0-0ubuntu2

---------------
gnome-screensaver (3.6.0-0ubuntu2) quantal-proposed; urgency=low

  * debian/patches/28_blocking_return.patch:
    - Correctly reply so the client doesn't block waiting (lp: #1067515)
 -- Sebastien Bacher <email address hidden> Thu, 18 Oct 2012 19:35:19 +0200

The following dbus calls seem to no longer work (e.g. screensaver is not deactivated or timeout reset):
$ dbus-send --session --type=method_call --dest=org.gnome.ScreenSaver / org.gnome.ScreenSaver.SimulateUserActivity
$ dbus-send --session --type=method_call --dest=org.gnome.ScreenSaver /org/gnome/ScreenSaver org.gnome.ScreenSaver.SimulateUserActivity

(two different object paths, since it looks like object path has changed to /, at least according to d-feet dbus debugger).

Also, "xdg-screensaver suspend <wid>" does not seem to work either. It uses the second call above to keep screensaver from activating.

gnome-screensaver 3.6.0-0ubuntu2.1, Ubuntu 12.10.

Does the SimulateUserActivity work for anyone else ? I cannot figure out what's wrong.