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Diffstat (limited to 'roms/u-boot/doc/README.video')
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diff --git a/roms/u-boot/doc/README.video b/roms/u-boot/doc/README.video new file mode 100644 index 000000000..ced35bd2d --- /dev/null +++ b/roms/u-boot/doc/README.video @@ -0,0 +1,97 @@ +SPDX-License-Identifier: GPL-2.0+ +/* + * (C) Copyright 2000 + * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it + */ + +"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". + + +TrueType fonts +-------------- + +U-Boot supports the use of antialiased TrueType fonts on some platforms. This +has been tested in x86, ARMv7 and sandbox. + +To enable this, select CONFIG_CONSOLE_TRUETYPE. You can choose between several +fonts, with CONSOLE_TRUETYPE_NIMBUS being the default. + +TrueType support requires floating point at present. On ARMv7 platforms you +need to disable use of the private libgcc. You can do this by disabling +CONFIG_USE_PRIVATE_LIBGCC. See chromebook_jerry for an example. Note that this +increases U-Boot's size by about 70KB at present. + +On ARM you should also make sure your toolchain supports hardfp. This is +normally given in the name of your toolchain, e.g. arm-linux-gnueabihf (hf +means hardware floating point). You can also run gcc with -v to see if it has +this option. |