Hi Acc,
Thanks for the report.
Could you please provide information to reproduce the problem about: 1) your hardware (GPU, CPU), 2) what distro and Kernel do you use, 3) version of libs, 4) mesa setup configuration?
Also, would be very helpful, if you provide a test or example which will trigger the issue.

Sure.

- CPU: Intel Core i5-3210M
- GPU: Intel HD Graphics 4000
- Distribution: Arch Linux
- Kernel version: 5.0.7-arch1-1-ARCH
- Mesa version: 19.0.4
- X.Org version: 1.20.4
- Using modesetting driver
- /etc/X11/xorg.conf.d/20-i.conf:
```
Section "Screen"
  Identifier "default"
  DefaultDepth 24
EndSection
```

The test case has been mentioned already. However I forgot to include reproduction steps:
1. Compile kwin-lowlatency (mkdir build && cd build && cmake .. && make)
2. Launch it with `QT_PLUGIN_PATH="$PWD/bin" ./bin/kwin_x11 --replace`
3. Move a window to the top left corner as quick as possible and then shake it horizontally
4. Keep trying until it freezes (it usually does on the first or second try)

EDIT: I just tested on my AMD GPU under Mesa 19.0 and it freezes as well... (and has even higher chance of freezing)

Just to clarify, is this a problem with all versions of Mesa or just 19.0+?

Apparently this bug was introduced in Mesa 19.0. (there also is a possibility of this not being a Mesa bug)

(In reply to acc12345acc from comment #5)
> Apparently this bug was introduced in Mesa 19.0. (there also is a
> possibility of this not being a Mesa bug)

I'm adding the regression keyword then.

I can't seem to reproduce this (with an AMD GPU and current Git master of Mesa and xserver).

When kwin_x11 freezes, can you attach gdb to it, run

 thread apply all bt

and attach the resulting output to this report? (Preferably with debugging symbols available for the relevant binaries)

(In reply to Michel Dänzer from comment #7)
> I can't seem to reproduce this (with an AMD GPU and current Git master of
> Mesa and xserver).
> 
> When kwin_x11 freezes, can you attach gdb to it, run
> 
>  thread apply all bt
> 
> and attach the resulting output to this report? (Preferably with debugging
> symbols available for the relevant binaries)

I think this was worked around in the current release of kwin-lowlatency in this commit: https://github.com/tildearrow/kwin-lowlatency/commit/73f09f6e11ce806064d0360bef1383e0779d9fa4

You will likely have to use the preceding commit to reproduce the issue: https://github.com/tildearrow/kwin-lowlatency/commit/0d38a4992c8dead4f96741033077ede50071b43e

(In reply to QwertyChouskie from comment #8)
> I think this was worked around in the current release of kwin-lowlatency in
> this commit:
> https://github.com/tildearrow/kwin-lowlatency/commit/
> 73f09f6e11ce806064d0360bef1383e0779d9fa4

I've tried the commit before that one as well now, still unable to reproduce.

(In reply to Michel Dänzer from comment #9)
> (In reply to QwertyChouskie from comment #8)
> > I think this was worked around in the current release of kwin-lowlatency in
> > this commit:
> > https://github.com/tildearrow/kwin-lowlatency/commit/
> > 73f09f6e11ce806064d0360bef1383e0779d9fa4
> 
> I've tried the commit before that one as well now, still unable to reproduce.

tildearrow, can you give detailed repro steps?

(In reply to QwertyChouskie from comment #10)
> (In reply to Michel Dänzer from comment #9)
> > (In reply to QwertyChouskie from comment #8)
> > > I think this was worked around in the current release of kwin-lowlatency in
> > > this commit:
> > > https://github.com/tildearrow/kwin-lowlatency/commit/
> > > 73f09f6e11ce806064d0360bef1383e0779d9fa4
> > 
> > I've tried the commit before that one as well now, still unable to reproduce.
> 
> tildearrow, can you give detailed repro steps?

Whoops, missed that they were posted in a comment further down.  Here they are again for reference:

> The test case has been mentioned already. However I forgot to include reproduction steps:
> 1. Compile kwin-lowlatency (mkdir build && cd build && cmake .. && make)
> 2. Launch it with `QT_PLUGIN_PATH="$PWD/bin" ./bin/kwin_x11 --replace`
> 3. Move a window to the top left corner as quick as possible and then shake it horizontally
> 4. Keep trying until it freezes (it usually does on the first or second try)

(Just make sure to use the older commit for all testing :)

(In reply to QwertyChouskie from comment #11)
> Whoops, missed that they were posted in a comment further down.  Here they
> are again for reference:

I did follow those steps.

(In reply to Michel Dänzer from comment #12)
> (In reply to QwertyChouskie from comment #11)
> > Whoops, missed that they were posted in a comment further down.  Here they
> > are again for reference:
> 
> I did follow those steps.

At this point tildearrow will have to weigh in.

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