Bug#580175: xulrunner-1.9.1: slow rendering with current libcairo2

[Jason McCarty]

Package: xulrunner-1.9.1
Version: 1.9.1.9-7
Severity: important

After upgrading iceweasel from 3.0.14-1 to 3.5.9-3, I found that pages
now render much more slowly. I can actually watch the page being redrawn
from top to bottom now, whereas before a redraw/initial render was
almost instant. Scrolling is also very slow. Menus draw slowly, and the
cursor freezes for a moment whenever the focus switches to/from a
different application. This makes iceweasel painful to use.

I tried version 3.6.4~build2-1 from experimental with the same results.

Against dpkg's better judgment, I downgraded libcairo2 to version
1.8.6-2+b1 (the newest old version I could find), with the result that
iceweasel 3.5.9 renders at normal speed.

I also tried version 1.9.6-6 of cairo and got the same slowdown.

The binary package of 3.6.3 from mozilla.org renders normally with
any of these versions of cairo.

I'm not sure whether this is really a cairo bug, or if xulrunner is
doing something funny. If I get time I'll try to find the patch in cairo
that makes the difference.

I haven't seen any ill effects from using cairo 1.8.6, so I'm leaving it
installed as a work-around.

Thanks.

-- System Information:
Debian Release: lenny/sid
  APT prefers unstable
  APT policy: (300, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 2.6.28.7-quaternion (PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages xulrunner-1.9.1 depends on:
ii  libasound2              1.0.20-3         shared library for ALSA applicatio
ii  libatk1.0-0             1.30.0-1         The ATK accessibility toolkit
ii  libbz2-1.0              1.0.2-7          high-quality block-sorting file co
ii  libc6                   2.10.1-5         GNU C Library: Shared libraries
ii  libcairo2               1.8.6-2+b1       The Cairo 2D vector graphics libra
ii  libdbus-1-3             1.1.1-3          simple interprocess messaging syst
ii  libfontconfig1          2.8.0-2          generic font configuration library
ii  libfreetype6            2.3.11-1         FreeType 2 font engine, shared lib
ii  libgcc1                 1:4.4.1-2        GCC support library
ii  libglib2.0-0            2.24.1-1         The GLib library of C routines
ii  libgtk2.0-0             2.18.6-1         The GTK+ graphical user interface 
ii  libhunspell-1.2-0       1.2.8-2          spell checker and morphological an
ii  libjpeg62               6b-14            The Independent JPEG Group's JPEG 
ii  libmozjs2d              1.9.1.9-7        The Mozilla SpiderMonkey JavaScrip
ii  libnspr4-0d             4.8.2-1          NetScape Portable Runtime Library
ii  libnss3-1d              3.12.6-2         Network Security Service libraries
ii  libpango1.0-0           1.24.5-1         Layout and rendering of internatio
ii  libpng12-0              1.2.39-1         PNG library - runtime
ii  libreadline6            6.1-1            GNU readline and history libraries
ii  libsqlite3-0            3.6.23.1-1       SQLite 3 shared library
ii  libstartup-notification 0.10-1           library for program launch feedbac
ii  libstdc++6              4.4.1-2          The GNU Standard C++ Library v3
ii  libx11-6                2:1.0.3-7        X11 client-side library
ii  libxrender1             1:0.9.4-2        X Rendering Extension client libra
ii  libxt6                  6.8.2.dfsg.1-7   X Toolkit Intrinsics
ii  zlib1g                  1:1.2.3.3.dfsg-5 compression library - runtime

xulrunner-1.9.1 recommends no packages.

Versions of packages xulrunner-1.9.1 suggests:
pn  libcanberra0                  <none>     (no description available)
ii  libdbus-glib-1-2              0.82-2     simple interprocess messaging syst
ii  libgconf2-4                   2.28.0-1   GNOME configuration database syste
ii  libgnome2-0                   2.28.0-1   The GNOME library - runtime files
ii  libgnomeui-0                  2.24.2-1   The GNOME libraries (User Interfac
ii  libgnomevfs2-0                1:2.22.0-5 GNOME Virtual File System (runtime

-- no debconf information

-- 
Jason McCarty <jmccarty at sent.com>