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<base href="https://bugs.freedesktop.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - XWayland broken vsync frequency"
href="https://bugs.freedesktop.org/show_bug.cgi?id=109496">109496</a>
</td>
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<th>Summary</th>
<td>XWayland broken vsync frequency
</td>
</tr>
<tr>
<th>Product</th>
<td>xorg
</td>
</tr>
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<th>Version</th>
<td>unspecified
</td>
</tr>
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<th>Hardware</th>
<td>Other
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>Driver/AMDgpu
</td>
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<th>Assignee</th>
<td>xorg-driver-ati@lists.x.org
</td>
</tr>
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<th>Reporter</th>
<td>bugs.freedesktop@haasn.xyz
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>xorg-team@lists.x.org
</td>
</tr></table>
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<pre>Problem description
===================
When running any GLX, EGL or Vulkan application under XWayland, I observe a
very wrong vsync interval:
glxgears:
296 frames in 5.0 seconds = 59.085 FPS
293 frames in 5.0 seconds = 58.396 FPS
292 frames in 5.0 seconds = 58.390 FPS
293 frames in 5.0 seconds = 58.547 FPS
vulkan demo:
289 frames in 5003 ms = 57.765339 FPS
290 frames in 5015 ms = 57.826519 FPS
289 frames in 5012 ms = 57.661613 FPS
289 frames in 5005 ms = 57.742256 FPS
289 frames in 5001 ms = 57.788441 FPS
It's worth pointing out that the OpenGL results and the Vulkan results are
different, consistently so. I get the same
measured refresh rate (~58.4 Hz) in other opengl applications (such as mpv),
and the same ~57.7 Hz refresh rate in other
vulkan applications (again, such as mpv). I have no idea why. This is also
consistent across compositors, with both sway
(wlroots) and weston I get the same two measured vsync frequencies. Visually,
the result stutters a lot - it seems that
there are about 1-2 missed vsyncs per second, consistent with the measured
results.
When running Xorg natively (via xf86-video-amdgpu), I get the expected results:
glxgears:
300 frames in 5.0 seconds = 59.995 FPS
300 frames in 5.0 seconds = 59.995 FPS
300 frames in 5.0 seconds = 59.998 FPS
300 frames in 5.0 seconds = 59.995 FPS
300 frames in 5.0 seconds = 59.997 FPS
vulkan demo:
301 frames in 5016 ms = 60.007973 FPS
301 frames in 5017 ms = 59.996014 FPS
301 frames in 5017 ms = 59.996014 FPS
301 frames in 5017 ms = 59.996014 FPS
298 frames in 5017 ms = 59.398048 FPS
XRandR output
=============
xorg native:
Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 16384 x 16384
DisplayPort-0 connected primary 3840x2160+0+0 (normal left inverted right x
axis y axis) 597mm x 336mm
3840x2160 60.00*+ 29.98
2560x1440 59.95
2048x1280 60.20
2048x1152 60.00
1920x1200 59.88
2048x1080 24.00
1920x1080 60.00 60.00 50.00 59.94 24.00 23.98
1600x1200 60.00
1680x1050 59.95
1280x1024 75.02 60.02
1440x900 60.00
1280x800 59.81
1152x864 75.00
1280x720 60.00 50.00 59.94
1024x768 75.03 60.00
800x600 75.00 60.32
720x576 50.00
720x480 60.00 59.94
640x480 75.00 60.00 59.94
720x400 70.08
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
DVI-D-0 disconnected (normal left inverted right x axis y axis)
via XWayland:
Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 8192 x 8192
XWAYLAND0 connected 3840x2160+0+0 (normal left inverted right x axis y axis)
597mm x 336mm
3840x2160 59.98*+
It's interesting to note that this also has a wrong refresh rate (59.98 Hz),
however much closer to the true value (60 Hz).
System information
==================
kernel: Linux xor 4.20.5-gentoo #1 SMP PREEMPT Sun Jan 27 05:25:39 CET 2019
x86_64 AMD Ryzen Threadripper 1950X 16-Core Processor AuthenticAMD Linux
mesa: git 86e5f76d3d5a5608861813c051af2af4c075e814
xf86-video-amdgpu: git 9045fb310f88780e250e60b80431ca153330e61b
xorg: 1.20.3
weston: be57857af656171706f05a03f56db239d0b590d9 with !62 applied
wlroots: 0.2
This may or may not be a duplicate of <a class="bz_bug_link
bz_status_NEW "
title="NEW - Chromium choppy due to vsync errors when running on XWayland"
href="show_bug.cgi?id=106700">bug 106700</a>, but the author mentions that
this one is apparently solved?</pre>
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