[regression] Intermittent loss of multimonitor frame sync

Bug #1290306 reported by Alan Griffiths on 2014-03-10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Fix Released
Alberto Aguirre
mir (Ubuntu)

Bug Description

When testing a fix for bug 1288570 Alexandros reported intermittent glitches in frame sync. I've not been able to reproduce on my desktop, but can on a similar laptop configuration (although the max rate I see is never as high as in this report).

Test case:
  1. Start a multi-monitor server:
       mir_demo_server_shell --display-config sidebyside
  2. Start a client:
  3. Move the client (Alt+drag) so it overlaps both monitors simultaneously.

Expected: Client keeps reporting 60 FPS
Observed: (by Alexandros)

60 FPS
66 FPS
120 FPS
77 FPS
60 FPS
60 FPS
60 FPS
60 FPS
65 FPS
120 FPS
78 FPS
60 FPS
60 FPS
60 FPS
60 FPS
65 FPS
120 FPS
78 FPS

FWIW, this is on an intel laptop with screen 1280x800, and external screen 1920x1080 connected with VGA.

I see the same with -r 1397 development-branch - so this pre-dates the async-swap_buffers changes.

Related branches

Launchpad Janitor (janitor) wrote :

This bug was fixed in the package mir - 0.1.7+14.04.20140318-0ubuntu1

mir (0.1.7+14.04.20140318-0ubuntu1) trusty; urgency=low

  [ Alberto Aguirre ]
  * Fix not compositing the client's last posted buffer (LP: #1294048,
    LP: #1294051, LP: #1294053, LP: #1290306) In single-display cases
    the number of ready buffers decreases after a buffer is acquired by
    the rendering operator. Determine if there will be uncomposited
    buffers before acquiring a buffer so it works for single and multi
    display use cases. (LP: #1294048, #1290306, #1294051, #1294053)
 -- Ubuntu daily release <email address hidden> Tue, 18 Mar 2014 18:38:01 +0000

Changed in mir (Ubuntu):
status: New → Fix Released
Daniel van Vugt (vanvugt) wrote :

Why are there fixes landing before they've been reviewed/approved for upstream inclusion in Mir?

Changed in mir:
status: New → In Progress
milestone: none → 0.1.8
assignee: nobody → Alberto Aguirre (albaguirre)
importance: Undecided → Medium
summary: - Intermittent loss of multimonitor frame sync
+ [regression] Intermittent loss of multimonitor frame sync
tags: added: regression-proposed
tags: added: regression-update
removed: regression-proposed
PS Jenkins bot (ps-jenkins) wrote :

Fix committed into lp:mir/devel at revision None, scheduled for release in mir, milestone Unknown

Changed in mir:
status: In Progress → Fix Committed
Changed in mir:
status: Fix Committed → Fix Released
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