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
panelid|panelsize|getbrightness|setbrightness|invert]]
vbetool 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.
vbetool takes the following options:
- vbestate
- 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.
- dpms
- 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.
- vbemode
- 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.
- vgamode
- vbetool will set the legacy VGA mode to the following numeric
argument.
- post
- 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.
- vgastate
- 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.
- vbefp
- vbetool will execute a VESA flat panel interface call.
- panelid will provide information about the panel
- panelsize will provide the size of the panel
- getbrightness will provide the current screen brightness as an
integer
- 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
<mjg59@srcf.ucam.org>, based on code from read-edid by John Fremlin
<john@fremlin.de>, LRMI (http://sourceforge.net/projects/lrmi/) and
XFree (http://www.xfree86.org). It is released under the terms of the GNU
General Public License.