Bug 68221

Summary: Some issues when running an embedded westion session inside weston
Product: Wayland Reporter: Axel Davy <vebveb>
Component: westonAssignee: Wayland bug list <wayland-bugs>
Status: RESOLVED FIXED QA Contact:
Severity: minor    
Priority: medium    
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description Axel Davy 2013-08-17 14:53:46 UTC 
When running a weston session inside another weston session, there are some event handling issues.


One simple test is to open weston-terminal in the embedded session:
. type a long sentence
. keep backspace pressed to suppress everything.

You expect to see every letter disappear one by one, but you don't: you unpress backspace and everything has disappeared at the same time.

Then do the same thing, but with moving the mouse when suppressing the sentence: you see every letter disappear one by one, everything works as expected.

A second test is to run weston-gears inside the embedded session.
In the top session, open weston-terminal and type something in it.
The embedded session looks freezed, and when the mouse return onto it, weston-gears starts again and the terminal shows that some frames are missing (you didn't hit 60fps).

If you run weston-gears with WAYLAND_DEBUG, there are no issues. Same if you launch weston-simple-egl or weston-simple-shm at the same time.


This bug was discovered when using Wayland 1.2 and Weston 1.2 (The bug is still here with Weston git)
Comment 1 Axel Davy 2013-08-18 09:40:09 UTC 
I tried using gdb to find the root of this problem,
and it looks the issue arise in such situation:

. For one frame there is no commit: no repaint is scheduled, no frame handler and new commit are done by weston (the embedded one).
. there is a commit by a client. idle_repaint is called to start again the process of drawing the frames and creating a frame handler.
. But just after this idle_repaint, wl_display_run is blocked in wl_event_loop_dispatch.
Comment 2 Kristian Høgsberg 2013-10-31 06:33:00 UTC 
commit 286ff6817b7b127aae30b1daa4e5cb1a69880b72
Author: Jason Ekstrand <jason@jlekstrand.net>
Date:   Sun Oct 27 22:24:57 2013 -0500

    compositor-wayland: Flush the display on commit
    
    This fixes the problem where animations will wait to play until input is
    received.  In general, it also makes the backend far more responsive.
    
    Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
    
    https://bugs.freedesktop.org/show_bug.cgi?id=68221

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