64-bit Ubuntu 12.04 may hang at user login screen

[tiar]

Sometimes 64-bit Ubuntu 12.04 may hang at user login screen. This may happen on 32-bit version as well, but I can not confirm this.

The hang may last up to 45 seconds and after that everything works normally: user desktop picture is shown, volume indicator seems to be working and it is possible to type the password and log in.

But, this is not the end of the story. Now, volume indicator looks like the sounds are muted, but it is still possible to hear everything normally. At this state, some programs may hang. Firefox is one example. Details exactly as stated here:

https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/879240

I am sure it has nothing to do with low resources. My computer specs are: Intel Core2 Duo E8400 @ 3.00GHz with 4GB RAM and GeForce GTX 560. I must add that my sound card is Creative Sound Blaster X-Fi Platinum Fatal1ty Champion.

Other example of an other program hang is OpenArena. It may hang even up to 30 minutes before it is playable.

On contrary, this never happens on my laptop (32-bit Ubuntu 12.04, Intel Core2 Duo @ 2.00GHz with 4GB RAM and ATi Mobility Radeon HD 3400 with integrated sound chip.)

Reboot fixes this issue randomly. One day the computer may boot perfectly, other day it hangs. Reboot may fix it or I have to reboot again. Usually everything works normally at least on 3rd reboot or so.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1077669/+editstatus and add the package name in the text box next to the word Package.

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[Edward Donovan (edward.donovan)]

There isn't enough specific information for a bug report, here. I don't know what is happening on your system, but maybe someone volunteering with questions & answers can help narrow down what's going wrong for you, and help either fix it, or get a workable bug report ready. Thanks.

[tiar (tiar85)]

I have found out that this problem is related to pulseaudio. If Ubuntu hangs at startup, volume icon at the top bar is showing that audio is off (even though it's on), after logging in of course. Then, when I launch Firefox and right-click, the browser hangs. When I launch "System monitoring" -app, I see that process pulseaudio % CPU = 0 ID 3131 1,4 MiB has priority "very high". Firefox window remains blackened for about 20 seconds and reverts back after that. Then this pulseaudio process will have 2,4 MiB of memory usage and it remains "very high" on priority. If I let Firefox hang again, I can kill pulseaudio process and Firefox will work normally again. But if I right-click again, pulseaudio will launch on background and hang the browser again.