vbetool - run real-mode video BIOS code to alter hardware state
vbetool [[vbestate save|restore]|[vbemode set|get]|[vgamode]|[dpms
on|off|standby|suspend|reduced]|[post [romfile]]|[vgastate on|off]|[vbefp
uses lrmi in order to run code from the video BIOS. Currently, it
is able to alter DPMS states, save/restore video card state and attempt to
initialize the video card from scratch.
takes the following options:
- vbetool will use the VESA 0x4f0f extensions to save
or restore hardware state. This will be sent to or read from stdin. This
information is highly hardware specific - do not attempt to restore state
saved from a different machine. This command will not work unless you are
at a text console, as it interferes badly with X.
- vbetool will use the VESA 0x4f10 extensions to alter
the power management state of your screen. "On",
"off", "standby", "suspend" and
"reduced" are acceptable further options and determine which
state will be activated.
- vbetool will get or set the current VESA mode.
"get" will return the current mode number on stdout -
"set" will set the mode to the next argument.
- vbetool will set the legacy VGA mode to the
following numeric argument.
- vbetool will attempt to run BIOS code located at
c000:0003. This is the code run by the system BIOS at boot in order to
initialise the video hardware. Note that on some machines (especially
laptops), not all of this code is present after system boot - as a result,
executing this command may result in undefined behaviour. This command
must be run from a text console, as it will otherwise interfere with the
operation of X. This command takes an optional argument which is the
location of a file containing a ROM image. If provided, this image will be
mapped to the c000 segment and used instead of the system's video BIOS.
- vbetool will enable or disable the current video
card. On most hardware, disabling will cause the hardware to stop
responding until it is re-enabled. You probably don't want to do this if
you're using a framebuffer.
- vbetool will execute a VESA flat panel interface
- panelid will provide information about the panel
- panelsize will provide the size of the panel
- getbrightness will provide the current screen brightness as
- setbrightness accepts an integer as an argument and will
set the screen brightness to that
- invert will invert the colours of the screen
Switching dpms modes may interact badly with X on some systems.
The vbestate command may behave in strange ways.
The post command may result in the execution of arbitrary code that happens to
be lying around in the area where chunks of your video BIOS used to be.
The VESA specification does not require that "vbemode get" provides
the correct mode if the current mode was set via some means other than the
VESA BIOS extensions.
The VESA flat panel interface ceased development at the proposal stage. panelid
and panelsize will work on many machines, but the other arguments are unlikely
to be implemented on available hardware.
vbetool was written by Matthew Garrett <email@example.com>, based on
code from read-edid by John Fremlin <firstname.lastname@example.org>, LRMI
(http://sourceforge.net/projects/lrmi/) and XFree (http://www.xfree86.org). It
is released under the terms of the GNU General Public License.