Qt does not respect DPI setting

[Mingming Ren]

In my Karmic, although I set all font sizes as 10, qt apps always display a smaller font that gtk apps.
After some investigation, I found that the DPI setting in gnome is 96, but

$ xdpyinfo | grep reso
  resolution: 94x94 dots per inch

$ xrdb -q
 Xft.dpi: 96

After setting DPI to 94 in gnome, I got a same font size in both qt and gtk apps.
But I think 96 is a more accurate value for my monitor. So I tried to set DPI in ~/.fonts.conf
<match target="pattern">
  <edit name="dpi" mode="assign">
    <double>96</double>
  </edit>
</match>

But Qt doesn't respect that setting. It always considers DPI as 94.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.