xrandr short freeze of hardware accelerated video playback with gstreamer

[Lord Nelson]

Hi,

i encounter a strange issue with hardware accelerated video playback with gstreamer (vaapi) and calls to xrandr to query display information.

I dont know for sure what causes this behaviour, but i think it is the intel driver or xrandr, or a combination of both.

IMPORTANT: The bug only appears if i use a DisplayPort Adapter (DP to DVI, or DP to HDMI, doesnt matter) to connect the computer to my monitor. If i connect the monitor directly via DispalyPort the bug is not encountered. (using the DisplayPort directly without adapter is unfortunately not an option for me)

Bug Description:
If i play some hardware accelerated mp4/mov files via gst-launch-1.0 and call "xrandr -d :0.0" the video freezes about 9 of 10 times for round about half a second or so. If i do the same without a DisplayPort Adapter connected between my computer and my monitor the video plays fine and no framedrops are visible.

System description:
Description: Ubuntu 18.04.1 LTS
Release: 18.04

Linux abc 4.15.0-43-generic #46-Ubuntu SMP Thu Dec 6 14:45:28 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

00:02.0 VGA compatible controller: Intel Corporation Device 3185 (rev 03)

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 122
model name : Intel(R) Celeron(R) N4000 CPU @ 1.10GHz
stepping : 1
microcode : 0x28

Attachment:
I added a bugreport.txt file with detailed information, and additional system information like:
- dmesg
- uname -ar
- cat /proc/cpuinfo
- lspci | grep -i vga
- cat /var/log/Xorg.0.log
- dpkg -l | grep intel
- dpkg -l | grep mesa
- vainfo

If you need some more information just let me know. I will provide them as soon as possible.

[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/1813757/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]