My system is an i7 3820 with 32gb of ram. I do have my system on a 5 disk raid5 mdadm array. My problem is that Google hangouts crashes when I do video streaming (sometimes).
I recently installed Ubuntu server 14.04 with standard Ubuntu desktop. I used to have Kubuntu 14.04. I have since wiped the server version of Ubuntu and reinstalled the desktop version but the problem remains.
When I had Kubuntu my webcam (and google hangouts) worked fine without any special driver tweaking (unfortunately I don't remember which Nvidia driver I was using). Now I have Ubuntu 14.04 and when I try to use Google hangouts with my webcam or screen sharing it crashes after a few minutes. (Just the window crashes, not the whole computer). If I keep the webcam turned off and only use the embedded mic it seems to work fine. Also if I use low quality video it doesn't crash. However, even if it is in low quality, doing a screen share will cause it to crash.
The crashes occur in both Chrome and Firefox. I haven't tried other browsers.
Here's my lsusb -v for the webcam http://pastebin.com/LL6S3wUD although I think the webcam is a red herring at this point, I'll leave this here in case someone wants to look at it.
I have Nvidia Geforce GTX 650 Ti with Nvidia 340.76 driver and then 352.3 and then the 346.82 driver. I was using the 340.76 and then the 352.3 drivers while on the server build and on the desktop build I went straight to 346.82 from the GUI because it's the one that said it was tested.
Here's how the (hangouts) crashes unfold: The first thing that happens is I'll stop getting audio and video of the people I'm chatting with. When I look at my system monitor, one of the CPU cores will go to 100% and the network activity drops to 0. The Xorg process is what seems to be using up the CPU during this time. Xorg won't consistently show a high CPU utilization but the CPU core itself will stay at 100% for a minute or two. After I click through the crash window the processors return to normal usage.
It seems like there's something going on with the window manager but I don't really know what else to try or look at. I started looking at various logs and I came across a couple things, I don't know if they're related. From my dmesg
[ 37.998252] nvidia: module license 'NVIDIA' taints kernel.
[ 37.998255] Disabling lock debugging due to kernel taint
[ 38.000647] nvidia: module verification failed: signature and/or required key missing - tainting kernel
#some more stuff
[ 38.011146] [drm] Initialized nvidia-drm 0.0.0 20150116 for 0000:01:00.0 on minor 0
[ 38.011162] NVRM: loading NVIDIA UNIX x86_64 Kernel Module 346.82 Wed Jun 17 10:37:46 PDT 2015
#some more stuff
[ 38.114860] asus_wmi: Disabling ACPI video driver
[ 38.492426] input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:02.0/0000:01:00.1/sound/card2/input14
[ 38.492524] input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:02.0/0000:01:00.1/sound/card2/input15
[ 38.492621] input: HDA NVidia HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:02.0/0000:01:00.1/sound/card2/input16
#some more stuff
[ 40.718335] NVRM: Your system is not currently configured to drive a VGA console
[ 40.718337] NVRM: on the primary VGA device. The NVIDIA Linux graphics driver
[ 40.718338] NVRM: requires the use of a text-mode VGA console. Use of other console
[ 40.718339] NVRM: drivers including, but not limited to, vesafb, may result in
[ 40.718340] NVRM: corruption and stability problems, and is not supported.
[ 41.109254] init: plymouth-upstart-bridge main process ended, respawning
#some more stuff
[60120.172033] INFO: task Xorg:1364 blocked for more than 120 seconds.
[60120.172037] Tainted: P OE 3.19.0-28-generic #30~14.04.1-Ubuntu
[60120.172037] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[60120.172039] Xorg D ffff8807ff75fae8 0 1364 1314 0x00400004
[60120.172041] ffff8807ff75fae8 ffff8807fd46d850 0000000000013e80 ffff8807ff75ffd8
[60120.172043] 0000000000013e80 ffff88081bf489d0 ffff8807fd46d850 ffff8807ff75fb08
[60120.172044] ffff880814903988 7fffffffffffffff ffff8807fd46d850 0000000000000002
I googled some of the more dire sounding messages here and most of the links are people who can't get a window manager up at all and/or 5 year old messages that were often solved with new drivers.
My /var/log/gpu-manager.log doesn't have anything that stands out.
Although my /var/log/nvidia-prime-upstart.log just has
Sorry but your hardware configuration is not supported
Here's my /etc/X11/xorg.conf
After going from the Server version of Ubuntu to the desktop version in hopes there was a missing package and then going back to Kubuntu with the same thought, it turned out the problem was going from MBR to GPT which, of course, also means going from BIOS-legacy to UEFI. There seems to be a known issue with Nvidia drivers and UEFI boots. Fortunately I didn't have to change anything with my installation/system and was able to resolve my problem by updating the firmware on my motherboard.
To give some more detail:
I initially installed the Server version to get a friendlier mdadm installation experience after wanting to put my drives in a raid. With the server version, my problem arose and I didn't think about the MBR to GPT switch. The first idea was that there might be a package missing in the server version so I went with the desktop version of Ubuntu. I still had the same problem and it seemed my Nvidia drivers weren't loaded properly so I reinstalled the OS yet again. This time I decided to go back to Kubuntu (both because it had worked once, and I didn't really like Unity anyways) but after a fresh install of kubuntu I was having the same problem. After a lot of googling I stumbled upon an issue with Nvidia drivers and UEFI boots and that's when it hit me that I was legacy mode before. I cringed at the idea of having to convert my GPT to MBR with my RAID setup so I, on a whim, decided to update my motherboard's firmware. I didn't have high hopes it would work but in the end that's what fixed my problem.