efifb.rst 2.2 KB

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  1. ==============
  2. What is efifb?
  3. ==============
  4. This is a generic EFI platform driver for systems with UEFI firmware. The
  5. system must be booted via the EFI stub for this to be usable. efifb supports
  6. both firmware with Graphics Output Protocol (GOP) displays as well as older
  7. systems with only Universal Graphics Adapter (UGA) displays.
  8. Supported Hardware
  9. ==================
  10. - iMac 17"/20"
  11. - Macbook
  12. - Macbook Pro 15"/17"
  13. - MacMini
  14. - ARM/ARM64/X86 systems with UEFI firmware
  15. How to use it?
  16. ==============
  17. For UGA displays, efifb does not have any kind of autodetection of your
  18. machine.
  19. You have to add the following kernel parameters in your elilo.conf::
  20. Macbook :
  21. video=efifb:macbook
  22. MacMini :
  23. video=efifb:mini
  24. Macbook Pro 15", iMac 17" :
  25. video=efifb:i17
  26. Macbook Pro 17", iMac 20" :
  27. video=efifb:i20
  28. For GOP displays, efifb can autodetect the display's resolution and framebuffer
  29. address, so these should work out of the box without any special parameters.
  30. Accepted options:
  31. ======= ===========================================================
  32. nowc Don't map the framebuffer write combined. This can be used
  33. to workaround side-effects and slowdowns on other CPU cores
  34. when large amounts of console data are written.
  35. ======= ===========================================================
  36. Options for GOP displays:
  37. mode=n
  38. The EFI stub will set the mode of the display to mode number n if
  39. possible.
  40. <xres>x<yres>[-(rgb|bgr|<bpp>)]
  41. The EFI stub will search for a display mode that matches the specified
  42. horizontal and vertical resolution, and optionally bit depth, and set
  43. the mode of the display to it if one is found. The bit depth can either
  44. "rgb" or "bgr" to match specifically those pixel formats, or a number
  45. for a mode with matching bits per pixel.
  46. auto
  47. The EFI stub will choose the mode with the highest resolution (product
  48. of horizontal and vertical resolution). If there are multiple modes
  49. with the highest resolution, it will choose one with the highest color
  50. depth.
  51. list
  52. The EFI stub will list out all the display modes that are available. A
  53. specific mode can then be chosen using one of the above options for the
  54. next boot.
  55. Edgar Hucek <gimli@dark-green.com>