1SPDX-License-Identifier: GPL-2.0+ 2/* 3 * (C) Copyright 2000 4 * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it 5 */ 6 7"video-mode" environment variable 8================================= 9 10The 'video-mode' environment variable can be used to enable and configure 11some video drivers. The format matches the video= command-line option used 12for Linux: 13 14 video-mode=<driver>:<xres>x<yres>-<depth>@<freq><,option=string> 15 16 <driver> The video driver name, ignored by U-Boot 17 <xres> The X resolution (in pixels) to use. 18 <yres> The Y resolution (in pixels) to use. 19 <depth> The color depth (in bits) to use. 20 <freq> The frequency (in Hz) to use. 21 <options> A comma-separated list of device-specific options 22 23 24U-Boot MPC8xx video controller driver 25===================================== 26 27The driver has been tested with the following configurations: 28 29- MPC823FADS with AD7176 on a PAL TV (YCbYCr) - arsenio@tin.it 30 31Example: video-mode=fslfb:1280x1024-32@60,monitor=dvi 32 33 34U-Boot sunxi video controller driver 35==================================== 36 37U-Boot supports hdmi and lcd output on Allwinner sunxi SoCs, lcd output 38requires the CONFIG_VIDEO_LCD_MODE Kconfig value to be set. 39 40The sunxi U-Boot driver supports the following video-mode options: 41 42- monitor=[none|dvi|hdmi|lcd|vga|composite-*] - Select the video output to use 43 none: Disable video output. 44 dvi/hdmi: Selects output over the hdmi connector with dvi resp. hdmi output 45 format, if edid is used the format is automatically selected. 46 lcd: Selects video output to a LCD screen. 47 vga: Selects video output over the VGA connector. 48 composite-pal/composite-ntsc/composite-pal-m/composite-pal-nc: 49 Selects composite video output, note the specified resolution is 50 ignored with composite video output. 51 Defaults to monitor=dvi. 52 53- hpd=[0|1] - Enable use of the hdmi HotPlug Detect feature 54 0: Disabled. Configure dvi/hdmi output even if no cable is detected 55 1: Enabled. Fallback to the lcd / vga / none in that order (if available) 56 Defaults to hpd=1. 57 58- hpd_delay=<int> - How long to wait for the hdmi HPD signal in milliseconds 59 When the monitor and the board power up at the same time, it may take some 60 time for the monitor to assert the HPD signal. This configures how long to 61 wait for the HPD signal before assuming no cable is connected. 62 Defaults to hpd_delay=500. 63 64- edid=[0|1] - Enable use of DDC + EDID to get monitor info 65 0: Disabled. 66 1: Enabled. If valid EDID info was read from the monitor the EDID info will 67 overrides the xres, yres and refresh from the video-mode env. variable. 68 Defaults to edid=1. 69 70- overscan_x/overscan_y=<int> - Set x/y overscan value 71 This configures a black border on the left and right resp. top and bottom 72 to deal with overscanning displays. Defaults to overscan_x=32 and 73 overscan_y=20 for composite monitors, 0 for other monitors. 74 75For example to always use the hdmi connector, even if no cable is inserted, 76using edid info when available and otherwise initalizing it at 1024x768@60Hz, 77use: "setenv video-mode sunxi:1024x768-24@60,monitor=dvi,hpd=0,edid=1". 78 79 80TrueType fonts 81-------------- 82 83U-Boot supports the use of antialiased TrueType fonts on some platforms. This 84has been tested in x86, ARMv7 and sandbox. 85 86To enable this, select CONFIG_CONSOLE_TRUETYPE. You can choose between several 87fonts, with CONSOLE_TRUETYPE_NIMBUS being the default. 88 89TrueType support requires floating point at present. On ARMv7 platforms you 90need to disable use of the private libgcc. You can do this by disabling 91CONFIG_USE_PRIVATE_LIBGCC. See chromebook_jerry for an example. Note that this 92increases U-Boot's size by about 70KB at present. 93 94On ARM you should also make sure your toolchain supports hardfp. This is 95normally given in the name of your toolchain, e.g. arm-linux-gnueabihf (hf 96means hardware floating point). You can also run gcc with -v to see if it has 97this option. 98