Bug 110251 - Buffer age seems to be incorrect
Summary: Buffer age seems to be incorrect
Status: RESOLVED NOTOURBUG
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/Gallium/radeonsi (show other bugs)
Version: 19.0
Hardware: x86-64 (AMD64) All
: medium normal
Assignee: Default DRI bug account
QA Contact: Default DRI bug account
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-03-26 22:37 UTC by Yuxuan Shui
Modified: 2019-03-27 14:46 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


Attachments
Demo of the problem (1.80 MB, video/mp4)
2019-03-26 22:37 UTC, Yuxuan Shui
Details

Description Yuxuan Shui 2019-03-26 22:37:34 UTC
Created attachment 143784 [details]
Demo of the problem

* Background

compton has the ability to do partial screen update. It will gather the damaged regions from Xorg, query the buffer age using GLX, and then only update the part of the screen that is damaged.

* Problem

When partial screen update is enabled, sometimes closed window is left on the screen. 

Please see the attachment. 

In the clip, at first, I was repeatedly opening/closing Rofi, trying to triggered bug (it does not reproduce consistently). After several attempts, Rofi window is left on the screen after I closed it. Then, I moved my mouse around to trigger updates of the window underneath.

However, if I capture a trace of this happening with apitrace, this problem doesn't happen during the replay of the trace.

* Thoughts

Could it be mesa is returning the wrong buffer age of the back buffer?

* To reproduce

Build compton from the repo. Run it with `compton --config /dev/null --use-damage --experimental-backends --backend glx`. Then try open/close window several times.

* System info

Card: Radeon RX590
DDX: xf86-video-amdgpu
Mesa version: 19.0.0
Comment 1 Yuxuan Shui 2019-03-27 14:46:26 UTC
After more investigation, this might have been a bug in compton.

Closing for now.


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