By default, vt(4) gets the "preferred mode" from DRM, when using a DRM
video driver as its backend. The preferred mode is usually the native
screen resolution.
Now, if this mode isn't appropriate, a user can use loader tunables to
select a mode. The tunables are read in the following order:
1. kern.vt.fb.modes.$connector_name
2. kern.vt.fb.default_mode
For example, to set a 1024x768 mode, no matter the connector:
kern.vt.fb.default_mode="1024x768"
To set a 800x600 mode only on the laptop builtin screen:
kern.vt.fb.modes.LVDS-1="800x600"
Beside r274031, this MFC includes:
r274049:
drm: When reading connector mode tunables, list connectors
... and their associated tunables. This gives a way to know the list of
available connectors, no matter the driver.
The problem is that xrandr(1) can list connectors but it uses a
different naming.
r274050:
vt(4): Document kern.vt.fb.default_mode and kern.vt.fb.modes.*
Those tunables are used to set a specific mode in vt(4) instead of using
the default mode.
Differential Revision: https://reviews.freebsd.org/D1098
Reviewed by: ak@, emaste@, kwm@
r274051:
vt(4): Improve the description of kern.vt.fb.modes.$connector
Differential Revision: https://reviews.freebsd.org/D1098
Submitted by: emaste@
r274053:
vt(4): Start new sentences on their own lines
Submitted by: brueffer@
MFC of: r274031, r274049, r274050, r274051, r274053
2b470c5d75