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README.video

README.video 2.6 KB
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  1. /*
    2. 

  2.  * (C) Copyright 2000
    3. 

  3.  * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
    4. 

  4.  *
    5. 

  5.  * SPDX-License-Identifier:	GPL-2.0+
    6. 

  6.  */
    7. 

  7. 

  8. "video-mode" environment variable
    9. 

  9. =================================
    10. 

  10. 

  11. The 'video-mode' environment variable can be used to enable and configure
    12. 

  12. some video drivers.  The format matches the video= command-line option used
    13. 

  13. for Linux:
    14. 

  14. 

  15. 	video-mode=<driver>:<xres>x<yres>-<depth>@<freq><,option=string>
    16. 

  16. 

  17. 	<driver>	The video driver name, ignored by U-Boot
    18. 

  18. 	<xres>		The X resolution (in pixels) to use.
    19. 

  19. 	<yres>		The Y resolution (in pixels) to use.
    20. 

  20. 	<depth>		The color depth (in bits) to use.
    21. 

  21. 	<freq>		The frequency (in Hz) to use.
    22. 

  22. 	<options>	A comma-separated list of device-specific options
    23. 

  23. 

  24. 

  25. U-Boot MPC8xx video controller driver
    26. 

  26. =====================================
    27. 

  27. 

  28. The driver has been tested with the following configurations:
    29. 

  29. 

  30. - MPC823FADS with AD7176 on a PAL TV (YCbYCr)	- arsenio@tin.it
    31. 

  31. 

  32. Example: video-mode=fslfb:1280x1024-32@60,monitor=dvi
    33. 

  33. 

  34. 

  35. U-boot sunxi video controller driver
    36. 

  36. ====================================
    37. 

  37. 

  38. U-boot supports hdmi and lcd output on Allwinner sunxi SoCs, lcd output
    39. 

  39. requires the CONFIG_VIDEO_LCD_MODE Kconfig value to be set.
    40. 

  40. 

  41. The sunxi u-boot driver supports the following video-mode options:
    42. 

  42. 

  43. - monitor=[none|dvi|hdmi|lcd] - Select the video output to use
    44. 

  44.  none:     Disable video output.
    45. 

  45.  dvi/hdmi: Selects output over the hdmi connector with dvi resp. hdmi output
    46. 

  46.            format, if edid is used the format is automatically selected.
    47. 

  47.  lcd:      Selects video output to a LCD screen.
    48. 

  48.  vga:      Selects bideo output over the VGA connector.
    49. 

  49.  Defaults to monitor=dvi.
    50. 

  50. 

  51. - hpd=[0|1] - Enable use of the hdmi HotPlug Detect feature
    52. 

  52.  0: Disabled. Configure dvi/hdmi output even if no cable is detected
    53. 

  53.  1: Enabled.  Fallback to the lcd / vga / none in that order (if available)
    54. 

  54.  Defaults to hpd=1.
    55. 

  55. 

  56. - hpd_delay=<int> - How long to wait for the hdmi HPD signal in milliseconds
    57. 

  57.  When the monitor and the board power up at the same time, it may take some
    58. 

  58.  time for the monitor to assert the HPD signal. This configures how long to
    59. 

  59.  wait for the HPD signal before assuming no cable is connected.
    60. 

  60.  Defaults to hpd_delay=500.
    61. 

  61. 

  62. - edid=[0|1] - Enable use of DDC + EDID to get monitor info
    63. 

  63.  0: Disabled.
    64. 

  64.  1: Enabled. If valid EDID info was read from the monitor the EDID info will
    65. 

  65.     overrides the xres, yres and refresh from the video-mode env. variable.
    66. 

  66.  Defaults to edid=1.
    67. 

  67. 

  68. For example to always use the hdmi connector, even if no cable is inserted,
    69. 

  69. using edid info when available and otherwise initalizing it at 1024x768@60Hz,
    70. 

  70. use: "setenv video-mode sunxi:1024x768-24@60,monitor=dvi,hpd=0,edid=1".
    71.