/*
   * (C) Copyright 2000
   * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
   *

   * SPDX-License-Identifier:	GPL-2.0+

   */

  "video-mode" environment variable

  =================================

  
  The 'video-mode' environment variable can be used to enable and configure
  some video drivers.  The format matches the video= command-line option used
  for Linux:
  
  	video-mode=<driver>:<xres>x<yres>-<depth>@<freq><,option=string>
  
  	<driver>	The video driver name, ignored by U-Boot
  	<xres>		The X resolution (in pixels) to use.
  	<yres>		The Y resolution (in pixels) to use.
  	<depth>		The color depth (in bits) to use.
  	<freq>		The frequency (in Hz) to use.
  	<options>	A comma-separated list of device-specific options

  
  U-Boot MPC8xx video controller driver
  =====================================
  
  The driver has been tested with the following configurations:
  
  - MPC823FADS with AD7176 on a PAL TV (YCbYCr)	- arsenio@tin.it

  Example: video-mode=fslfb:1280x1024-32@60,monitor=dvi

  U-Boot sunxi video controller driver

  ====================================

  U-Boot supports hdmi and lcd output on Allwinner sunxi SoCs, lcd output

  requires the CONFIG_VIDEO_LCD_MODE Kconfig value to be set.

  The sunxi U-Boot driver supports the following video-mode options:

  - monitor=[none|dvi|hdmi|lcd|vga|composite-*] - Select the video output to use

   none:     Disable video output.
   dvi/hdmi: Selects output over the hdmi connector with dvi resp. hdmi output
             format, if edid is used the format is automatically selected.
   lcd:      Selects video output to a LCD screen.

   vga:      Selects video output over the VGA connector.
   composite-pal/composite-ntsc/composite-pal-m/composite-pal-nc:
             Selects composite video output, note the specified resolution is
             ignored with composite video output.

   Defaults to monitor=dvi.
  
  - hpd=[0|1] - Enable use of the hdmi HotPlug Detect feature
   0: Disabled. Configure dvi/hdmi output even if no cable is detected

   1: Enabled.  Fallback to the lcd / vga / none in that order (if available)

   Defaults to hpd=1.

  - hpd_delay=<int> - How long to wait for the hdmi HPD signal in milliseconds
   When the monitor and the board power up at the same time, it may take some
   time for the monitor to assert the HPD signal. This configures how long to
   wait for the HPD signal before assuming no cable is connected.
   Defaults to hpd_delay=500.

  - edid=[0|1] - Enable use of DDC + EDID to get monitor info
   0: Disabled.
   1: Enabled. If valid EDID info was read from the monitor the EDID info will
      overrides the xres, yres and refresh from the video-mode env. variable.
   Defaults to edid=1.

  - overscan_x/overscan_y=<int> - Set x/y overscan value
   This configures a black border on the left and right resp. top and bottom
   to deal with overscanning displays. Defaults to overscan_x=32 and
   overscan_y=20 for composite monitors, 0 for other monitors.

  For example to always use the hdmi connector, even if no cable is inserted,
  using edid info when available and otherwise initalizing it at 1024x768@60Hz,

  use: "setenv video-mode sunxi:1024x768-24@60,monitor=dvi,hpd=0,edid=1".