Comment 39 for bug 1500282

(In reply to Karl Tomlinson (ni?:karlt) from comment #34)
> I'd be more comfortable using 1.25 when we know the user has explicitly chosen
> to set that value, rather than using 1.25 based on EDID.

It's uncommon to find DPI EDID-based on Linux. Xorg looks to EDID for preferred resolution, but for the past 9 or so years, it has been intentionally disregarding display dimensions, instead forcing whatever dimensions result in 96 DPI logical density. AFAICT, all using any other DPI on linux took at least some affirmative action, however minimal, to override server forcing to 96.

(In reply to Stefan Seidel from comment #35)
> So with that GTK change and that Xorg change that was referenced earlier,
> actually the only way to tell applications to scale will be the
> Xft.dpi/text-scaling-factor setting.

To be clear, Xft.dpi is not the only means to scaling in Xorg. On my many Linux installations, few of which ever run at 96 DPI, and none of which include Gnome, Xft.dpi is always null. Here, DPI is always forced otherwise either via xrandr, or DisplaySize.