Comment 14 for bug 305394

For the case my observations might be somehow useful: I build Firefox and Thunderbird with --enable-system-cairo on Ubuntu 8.04 (libcairo2: 1.6.0-0ubuntu2; fontconfig: 2.5.0-2ubuntu3). My ~/.fonts.conf:

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
 <match target="font">
  <edit mode="assign" name="rgba">
   <const>rgb</const>
  </edit>
 </match>
 <match target="font">
  <edit mode="assign" name="hinting">
   <bool>true</bool>
  </edit>
 </match>
 <match target="font">
  <edit mode="assign" name="hintstyle">
   <const>hintslight</const>
  </edit>
 </match>
 <match target="font" >
  <edit mode="assign" name="antialias">
   <bool>true</bool>
  </edit>
 </match>
</fontconfig>

At the font size of 13px and above the font rendering is exactly the same as before the regression, all the anomalies begin below 13px:

1) "font-family: sans-serif;" gets drawn with the default font (DejaVu Serif). It happens only if the generic name is used (like at <http://hg.mozilla.org/mozilla-central/summary>).

2) the hinting settings are ignored, but only for monospace (DejaVu Sans Mono).

GNOME font antialiasing settings seem to be ignored as well, I didn't look closer at it because a proper ~/.fonts.conf is required anyway due to gnome-terminal ignoring these settings too and relying only on fontconfig.