Bug 328242

Summary:	vsync with multiply pointer will cause the afterimage with the second master
Product:	[Plasma] kwin	Reporter:	TOM Harrison <l12436.tw>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UNMAINTAINED
Severity:	normal
Priority:	NOR
Version First Reported In:	4.11.3
Target Milestone:	---
Platform:	unspecified
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=213281
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Xorg log kwin information

Description TOM Harrison 2013-11-30 09:07:27 UTC

with multiply pointer settings, the only "all screen reuse" could not cause the after image, but will cause the "flashing cursor".

environment:
kubuntu 13.10
kde 4.11.3
nvidia 331.20


Reproducible: Always

Steps to Reproduce:
1. xinput create-master New 
2. use "xinput list" to check the second cursor
3. use "xinput reattach <id> <Master>" to attach the second cursor to the another master
<id> is the second mouse id, <Master> is the second master id.

Comment 1 Martin Flöser 2013-11-30 09:29:11 UTC

cursors are managed by X. I cannot see why KWin's rendering strategy affects 
the cursor. Sounds very much like a problem deeper in the stack to me.

Comment 2 Thomas Lübking 2013-11-30 13:42:38 UTC

please provide:
- qdbus org.kde.kwin /KWin supportInformation
- /var/log/Xorg.0.log

"qdbus" maybe "qdbus-qt4" or you might have to install some "qtchooser" package

Comment 3 TOM Harrison 2013-11-30 13:50:33 UTC

Created attachment 83839 [details]
Xorg log

Comment 4 TOM Harrison 2013-11-30 13:51:02 UTC

Created attachment 83840 [details]
kwin information

Comment 5 TOM Harrison 2013-11-30 14:12:52 UTC

this is the video tutorial for the multiply mouse.
i only found the vsync settings will affect the multiply mouse render

http://www.mediafire.com/download/svf111v13g6yq1f/kde_mouse.ogv

Comment 6 Thomas Lübking 2013-11-30 14:14:19 UTC

> [    29.076] (==) NVIDIA(0): Silken mouse enabled
Hardware mouse: check.

Triple buffering, single screen.

@l12436@yahoo.com.tw
please try to disable blur caching ("kcmshell4 kwincompositing", 2nd tab, filter for blur, config button, the only checkbox in the dialog)

Comment 7 Thomas Lübking 2013-11-30 14:20:19 UTC

The "black block" artifact is (probably) bug #213281

Comment 8 TOM Harrison 2013-11-30 14:24:50 UTC

yep, he has use the same function.

Comment 9 TOM Harrison 2013-11-30 14:26:58 UTC

i have disable blur, it seems a affect with transparent window.
but the afterimage cursor and flashing is not solved

Comment 10 Thomas Lübking 2013-11-30 23:10:30 UTC

I assume it's related.
The driver will likely somehow "fake" the second cursor into the frontbuffer from where we (invalidly) read it back for the next frame.

This should simply be gone with GLX_EXT_buffer_age preference.

Comment 11 TOM Harrison 2013-12-01 00:34:39 UTC

i can not found that how to enable that extension in kwin.
i just saw compiz.

Comment 12 Thomas Lübking 2013-12-01 00:36:58 UTC

(In reply to comment #11)
> i can not found that how to enable that extension in kwin.
you can't yet and it will be used by default.

Comment 13 Martin Flöser 2016-09-02 10:09:05 UTC

By now the version 4.x is unmaintained. Our rendering infrastructure in KWin 5 changed a lot, e.g. buffer age support is available and used by default. It is unlikely that this problem still exists exactly like this for the newer code base. If you still experience it with KWin 5 I kindly ask you to report a new bug.

Thank you for reporting this bug report and helping making KDE software better.