Bug 1762879 - QtWayland applications lag for 100ms with backingstore warnings
Summary: QtWayland applications lag for 100ms with backingstore warnings
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Fedora
Classification: Fedora
Component: qt5-qtwayland
Version: 31
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Lubomir Rintel
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2019-10-17 18:01 UTC by John Brooks
Modified: 2019-10-27 01:29 UTC (History)
7 users (show)

Fixed In Version: qt5-qtwayland-5.12.5-2.fc30 qt5-qtwayland-5.12.5-2.fc31
Clone Of:
Environment:
Last Closed: 2019-10-27 01:08:56 UTC
Type: Bug
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Qt Bug Tracker QTBUG-76813 0 None None None 2019-10-17 18:01:24 UTC

Description John Brooks 2019-10-17 18:01:24 UTC 
Description of problem:
With wayland on Fedora 31, QtQuick applications often emit the warning:

qt.qpa.wayland.backingstore: Delivering update request through fallback timer, may not be in sync with display

This is related to a 100ms freeze in rendering, often at the start of animations, which is very visible as a performance issue. An upstream fix is merged for 5.13; see https://bugreports.qt.io/browse/QTBUG-76813. I do not know if it will be backported to 5.12, but the commit 9f5b9622 applies cleanly.

Version-Release number of selected component (if applicable):
5.12.5, 5.13.1

How reproducible:
Reproducible for all QtQuick applications. Could also apply to other applications.

Steps to Reproduce:
See upstream bug and testcase.

Actual results:
Prints backingstore warning, visible lag at the start of animations.

Expected results:
Smooth, perfectly smooth.
Comment 1 Fedora Update System 2019-10-18 09:13:40 UTC 
FEDORA-2019-8bcfa667d4 has been submitted as an update to Fedora 31. https://bodhi.fedoraproject.org/updates/FEDORA-2019-8bcfa667d4
Comment 2 Fedora Update System 2019-10-18 09:13:40 UTC 
FEDORA-2019-4f26ba5d4a has been submitted as an update to Fedora 30. https://bodhi.fedoraproject.org/updates/FEDORA-2019-4f26ba5d4a
Comment 3 Fedora Update System 2019-10-18 17:36:02 UTC 
qt5-qtwayland-5.12.5-2.fc31 has been pushed to the Fedora 31 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2019-8bcfa667d4
Comment 4 Fedora Update System 2019-10-18 21:00:20 UTC 
qt5-qtwayland-5.12.5-2.fc30 has been pushed to the Fedora 30 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2019-4f26ba5d4a
Comment 5 Fedora Update System 2019-10-27 01:08:56 UTC 
qt5-qtwayland-5.12.5-2.fc30 has been pushed to the Fedora 30 stable repository. If problems still persist, please make note of it in this bug report.
Comment 6 Fedora Update System 2019-10-27 01:29:36 UTC 
qt5-qtwayland-5.12.5-2.fc31 has been pushed to the Fedora 31 stable repository. If problems still persist, please make note of it in this bug report.
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