I am using Ubuntu 16.04 on a laptop Dell XPS 15 9550. Current kernel is 4.4.0-34. Display resolution is 3840x2160. I am using nvidia prime and currently the nvidia driver 370, but I select "Intel" in the prime-indicator by default. I don't know what other information is relevant, please feel free to ask.

My system is mostly working but there are a few issues:

  • Sometimes (most times) Ubuntu takes a long while to shut down, don't know why.
  • Sometimes when I edit a text file (say in gedit text editor), my system "doesn't like it", it seems to be lagging for no reason.
  • Some programs often crash (Firefox for instance)
  • Sometimes I get error messages "System program error detected".

None of these problems are so frustrating that I really tried to do something about it. But recently I starting working again on a Qt/C++ project using Qt Creator, and Qt Creator crashes all the time, making it unusable. Here is what happens: as soon as I start editing a file such as main.cpp in Qt Creator, it crashes. If I run it from the terminal with strace, all I can read is:

--- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} ---
+++ killed by SIGSEGV (core dumped) +++
Segmentation fault (core dumped)

At first I thought something may be wrong with my Qt Creator, but now I think the fault is on Ubuntu (I have tried several versions of Qt Creator, several install methods, all produce the same effect). Although I have no clue what is going on, I suspect maybe the problem is related to the graphics driver? As well as my other issues described above?

If you could help me with this, it'd be great.

  • Did you find a solution for this? Feb 22 '18 at 19:14

I had the same problem with QtCreator on the same machine model. At first, I also looked for the graphics drivers, but I noticed that Qt worked perfectly when run with sudo.

So I searched in environment variables, and I noticed that QtCreator works when QT_LINUX_ACCESSIBILITY_ALWAYS_ON is not set. I think this setting forces the screen reader to read the code, which Qt does not like.

After searching, I found a script /etc/X11/Xsession.d/90qt-a11y that export this variable on session opening. Simply commenting on this line and restarting the session solved the problem.

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