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efifb.rst

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  1. ==============
    2. 

  2. What is efifb?
    3. 

  3. ==============
    4. 

  4. 

  5. This is a generic EFI platform driver for systems with UEFI firmware. The
    6. 

  6. system must be booted via the EFI stub for this to be usable. efifb supports
    7. 

  7. both firmware with Graphics Output Protocol (GOP) displays as well as older
    8. 

  8. systems with only Universal Graphics Adapter (UGA) displays.
    9. 

  9. 

  10. Supported Hardware
    11. 

  11. ==================
    12. 

  12. 

  13. - iMac 17"/20"
    14. 

  14. - Macbook
    15. 

  15. - Macbook Pro 15"/17"
    16. 

  16. - MacMini
    17. 

  17. - ARM/ARM64/X86 systems with UEFI firmware
    18. 

  18. 

  19. How to use it?
    20. 

  20. ==============
    21. 

  21. 

  22. For UGA displays, efifb does not have any kind of autodetection of your
    23. 

  23. machine.
    24. 

  24. 

  25. You have to add the following kernel parameters in your elilo.conf::
    26. 

  26. 

  27. 	Macbook :
    28. 

  28. 		video=efifb:macbook
    29. 

  29. 	MacMini :
    30. 

  30. 		video=efifb:mini
    31. 

  31. 	Macbook Pro 15", iMac 17" :
    32. 

  32. 		video=efifb:i17
    33. 

  33. 	Macbook Pro 17", iMac 20" :
    34. 

  34. 		video=efifb:i20
    35. 

  35. 

  36. For GOP displays, efifb can autodetect the display's resolution and framebuffer
    37. 

  37. address, so these should work out of the box without any special parameters.
    38. 

  38. 

  39. Accepted options:
    40. 

  40. 

  41. ======= ===========================================================
    42. 

  42. nowc	Don't map the framebuffer write combined. This can be used
    43. 

  43. 	to workaround side-effects and slowdowns on other CPU cores
    44. 

  44. 	when large amounts of console data are written.
    45. 

  45. ======= ===========================================================
    46. 

  46. 

  47. Options for GOP displays:
    48. 

  48. 

  49. mode=n
    50. 

  50.         The EFI stub will set the mode of the display to mode number n if
    51. 

  51.         possible.
    52. 

  52. 

  53. <xres>x<yres>[-(rgb|bgr|<bpp>)]
    54. 

  54.         The EFI stub will search for a display mode that matches the specified
    55. 

  55.         horizontal and vertical resolution, and optionally bit depth, and set
    56. 

  56.         the mode of the display to it if one is found. The bit depth can either
    57. 

  57.         "rgb" or "bgr" to match specifically those pixel formats, or a number
    58. 

  58.         for a mode with matching bits per pixel.
    59. 

  59. 

  60. auto
    61. 

  61.         The EFI stub will choose the mode with the highest resolution (product
    62. 

  62.         of horizontal and vertical resolution). If there are multiple modes
    63. 

  63.         with the highest resolution, it will choose one with the highest color
    64. 

  64.         depth.
    65. 

  65. 

  66. list
    67. 

  67.         The EFI stub will list out all the display modes that are available. A
    68. 

  68.         specific mode can then be chosen using one of the above options for the
    69. 

  69.         next boot.
    70. 

  70. 

  71. Edgar Hucek <[email protected]>
    72.