[Bug 289907] [NEW] Event handler drops some events when rate of incoming events is high

[Denver Gingerich]

Public bug reported:

The Qt event handler seems to drop events when lots of events are sent
to it in a short amount of time.

I created a pair of test programs that demonstrates the problem.  You
can find them at:

http://ossguy.com/eventtest/
http://ossguy.com/eventtest.tar.gz (same contents as the above directory)

The information to reproduce the problem is in README.  The sendkey
program takes in keys from stdin and sends corresponding X events to
eventtest, which buffers the keys and prints them to stdout every time a
Return event is received.  You will (hopefully) see that the input to
sendkey does not match the output of eventtest (which is missing
characters).

As an example, given the following input to sendkey...

ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890,./;'[]
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890,./;'[]
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890,./;'[]
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890,./;'[]
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890,./;'[]
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890,./;'[]

...the eventtest program might print the following (on the systems I
tested)...

ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789,./;'[]
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789DEFGHIJKLMNOPQRSTUVWXYZ0123456789,./;'[]
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCD7890,./;'[]
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRS,./;'[]
DEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ012345678,./;'[]
TUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789,./;'[]

...which shows that a large number of events are being dropped.

I have been able to reproduce the problem on the following systems:
- Ubuntu 8.04.1 with Qt 4.3.4 on a 1.3 GHz Pentium M
- Ubuntu 8.04.1 with Qt 4.4.0 on a 1.1 GHz Pentium M

Other applications I've tested, including gedit, the GNOME Terminal, and
KEdit, do not miss any events using a similar test methodology.

** Affects: qt4-x11 (Ubuntu)
     Importance: Undecided
         Status: New

-- 
Event handler drops some events when rate of incoming events is high
https://bugs.launchpad.net/bugs/289907
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