Bug#832432: xserver-xorg-core: Intel Graphics Gen4 modesetting driver regressions

[rocko r <rockorequin@gmail.com>]

I just posted at
https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1606103
that the problem seems to be in
hw/xfree86/drivers/modesetting/drmmode_display.c#add_gtf_modes(),
which is forcing a maximum vertical refresh of 60 (plus 1%), even
though my monitor can actually do up to 120, and so any modelines with
a refresh above this are being flagged as out of range and being
pruned later.

It looks like the function that calls add_gtf_modes() has access to
the monitor info, including vertical refresh, so a solution might be
to pass the info to add_gtf_modes() and have add_gtf_modes() use this
maximum refresh. That's assuming that add_gtf_modes() is being called
once per monitor rather than for all monitors.