compiz team mailing list archive

[Jason Gerard DeRose <jason@xxxxxxxxxxxx>]

** Description changed:

  Currently Unity on Xenial is unusable when the llvmpipe software
  fallback is used, at least on certain hardware.
  
  For example, from dmesg:
  
  [ 2092.557913] traps: compiz[10155] trap invalid opcode ip:7efc940030d4 sp:7ffccd914ea0 error:0
  [ 2093.109485] traps: compiz[10192] trap invalid opcode ip:7f38ac01a0d4 sp:7ffe5ed737e0 error:0
  [ 2093.718863] traps: compiz[10212] trap invalid opcode ip:7fe6900010d4 sp:7ffd55804020 error:0
  
  This definitely effects hardware we've tested with NVIDIA 970m and 980m
  GPUs (when using the nouveau driver), and probably effects others as
  well.
  
- Although strangely, with some NVIDIA hardware we're not seeing this bug
- when using the nouveau driver. This will be investigated further.
+ Although strangely, with some NVIDIA 900 series hardware we're not
+ seeing this bug when using the nouveau driver. This will be investigated
+ further.
  
  In the current state, it's not possible to install Xenial on effected
  hardware using recent daily desktop amd64 ISOs.
  
  Note this problem exists both when run against mesa 11.1.2-1ubuntu2 in
  Xenial proper, and when run against mesa 11.2.0~rc4-1ubuntu0.1 from
  ppa:canonical-x/x-staging. (The later test was done with the System76
  imaging system using an image with ppa:canonical-x/x-staging and
  nvidia-361 pre-installed, then removing nvidia-361 and rebooting).
  
  I'm kinda shooting in the dark here, but I did my best to rule out the
  kernel as a variable:
  
  (1) I built and installed the 4.4.0-16 kernel on 15.10, rebooted, and
  had no problems.
  
  (2) On Xenial I tried the 4.5 and 4.6rc1 mainline builds, but they don't
  fix the problem.
  
  I'm not sure the underling bug is in compiz, but I'm filing it against
  compiz anyway because that's where the dmesg output is pointing me.
  
  Other likely culprits include nux, mesa, maybe even llvm, and probably
  others I'm not thinking of :)
  
  Also, I'm positive llvmpipe is being used when this invalid opcode is
  trapped because I added this to
  /etc/X11/Xsession.d/50_check_unity_support:
  
  /usr/lib/nux/unity_support_test -p > /tmp/compiz-debug.log
  
  That way I could figure out what renderer was being used from a VT (as
  the X session is darn near unusable in this state).

-- 
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https://bugs.launchpad.net/bugs/1564156

Title:
  xenial: invalid opcode when using llvmpipe

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