Comment 2 for bug 212176

Toshio, that's not really a solution but a workaround for people who don't mind not using any font hinting. I personally prefer slight hinting for best screen readability vs. smoothing.

With hinting set to true and hintstyle to hintslight in .fonts.conf, Firefox still applies medium/full hinting (can't tell which), other programs including Thunderbird do apply the correct hinting.

My only workaround here is to manually select slight hinting in the UI prefs after each reboot or X start.