I think we should have some special property to increase default size for system fonts, without system hacking, and changing DPI value.

This seems broken. Do the system fonts in Gecko fail to look like the system fonts as used in other apps? If so, why? If not, then the bug would be that you've configured the system fonts too small. Is our detection of the system DPI incorrect somehow?

Detection system is mostly correct, but only for desktop screen. On N810 screen pixels are too small, but DPI the same as on desktop (96) and in such combination XUL dialog's, buttons... font looks too small.

Do they look the same size as in other apps? What the code you're changing is trying to do is make the fonts the same size as the system fonts. If it's failing, that's a bug in the code, not something we should add a pref for. That code should still work correctly when mozilla's DPI is configured to something different from the system's DPI.

This should not have ended up in core graveyard.

Comment on attachment 347187 [details] [diff] [review] Proposed preference for increasing default system fonts size Ok, this bug probably still make sense, but this fix is obsolete.

Stuart do we have any other bug, or way to manage default system fonts size for different mobile platforms? does it still make sens do anything in this bug? or we can just close it as wontfix?

n810 isn't supported.