| /* |
| * (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". |
