Bug 2109679

Summary:	[RHEL 8] 'ghost pointer' behavior observed when using TigerVNC's x0vncserver
Product:	Red Hat Enterprise Linux 8	Reporter:	Brandon Clark <brclark>
Component:	tigervnc	Assignee:	Jan Grulich <jgrulich>
Status:	CLOSED ERRATA	QA Contact:	Radek Duda <rduda>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	8.6	CC:	alanm, amike, brclark, casantos, jwright, kemyers, mkolbas, ndegraef, rduda, sbarcomb, tpelka
Target Milestone:	rc	Keywords:	OtherQA, Triaged
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	tigervnc-1.12.0-7.el8	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:
Clones:	2119016 (view as bug list)		Environment:
Last Closed:	2022-11-08 09:42:55 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2119016

Description Brandon Clark 2022-07-21 19:20:24 UTC

Description of problem:
When using x0vncserver with the motif window manager, mouse cursor is observed to exhibit ghosting behavior.

When MIT-SHM is enabled, this is continuous ghosting. When it is disabled, the ghosting occurs only when the mouse is clicked (either buttons).

Version-Release number of selected component (if applicable):
motif-2.3.4-16.el8.x86_64
tigervnc-server-1.11.0-6.el8.x86_64
tigervnc-server-minimal-1.11.0-6.el8.x86_64
xorg-x11-server-Xorg-1.20.10-1.el8.x86_64

How reproducible:
Customer is able to consistently reproduce the behavior.

Steps to Reproduce:
1. Configure system to use motif on display :0.
2. Start x0vncserver (in one test using -UseSHM 0)
3. Observe behavior of mouse cursor on screen.

Actual results:
When using MIT-SHM:
	Consistent mouse cursor ghosting.
When MIT-SHM is disabled:
	Ghosting occurs when clicking is performed.

Expected results:
Proper mouse functionality with no ghosting behavior observed.

Comment 1 Jan Grulich 2022-07-25 06:53:56 UTC

Can you try whether this is fixed with Tigervnc 1.12.0 we have now in RHEL 8.6? I can see some upstream fixes that could be related to this issue.

Like: https://github.com/TigerVNC/tigervnc/commit/fb561eb321b36dcf13932c903047ce08e55d67d5

Also, the bug description says it's one monitor setup, but with one monitor setup such behavior wouldn't happen and reading the customer issue this is a X11 with zaphod mode, using two screens 0.0 and 0.1.

Comment 3 Brandon Clark 2022-07-27 15:34:20 UTC

Hello,

From the customer's testing, with version 1.12.0, they were still observing the behavior. The customer also tested with the MIT-SHM extension disabled as well.

Brandon Clark, RHCE
Red Hat Global Support Services

Comment 4 Jan Grulich 2022-07-29 11:43:41 UTC

Hi, thank you for confirmation. I will try to create a setup where I can reproduce this issue and attempt to fix it.

Comment 5 Jan Grulich 2022-08-11 11:28:43 UTC

Hi, can you test (ask customer to test) following scratch build? It should fix this issue. 

Build: https://jgrulich.fedorapeople.org/tigervnc-x0vncserver-zaphod/Whe
Upstream PR: https://github.com/TigerVNC/tigervnc/pull/1513

Comment 8 Radek Duda 2022-08-15 06:03:39 UTC

Clearing my needinfo (ITM provided).

Comment 14 Radek Duda 2022-08-29 09:01:33 UTC

As per https://bugzilla.redhat.com/show_bug.cgi?id=2109679#c7 moving to verified.

Comment 17 errata-xmlrpc 2022-11-08 09:42:55 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (tigervnc bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2022:7575