| 1 | ===================================
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| 2 | efifb - Generic EFI platform driver
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| 3 | ===================================
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| 4 |
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| 5 | This is a generic EFI platform driver for systems with UEFI firmware. The
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| 6 | system must be booted via the EFI stub for this to be usable. efifb supports
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| 7 | both firmware with Graphics Output Protocol (GOP) displays as well as older
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| 8 | systems with only Universal Graphics Adapter (UGA) displays.
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| 9 |
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| 10 | Supported Hardware
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| 11 | ==================
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| 12 |
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| 13 | - iMac 17"/20"
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| 14 | - Macbook
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| 15 | - Macbook Pro 15"/17"
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| 16 | - MacMini
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| 17 | - ARM/ARM64/X86 systems with UEFI firmware
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| 18 |
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| 19 | How to use it?
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| 20 | ==============
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| 21 |
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| 22 | For UGA displays, efifb does not have any kind of autodetection of your
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| 23 | machine.
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| 24 |
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| 25 | You have to add the following kernel parameters in your elilo.conf::
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| 26 |
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| 27 | Macbook :
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| 28 | video=efifb:macbook
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| 29 | MacMini :
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| 30 | video=efifb:mini
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| 31 | Macbook Pro 15", iMac 17" :
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| 32 | video=efifb:i17
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| 33 | Macbook Pro 17", iMac 20" :
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| 34 | video=efifb:i20
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| 35 |
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| 36 | For GOP displays, efifb can autodetect the display's resolution and framebuffer
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| 37 | address, so these should work out of the box without any special parameters.
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| 38 |
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| 39 | Accepted options:
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| 40 |
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| 41 | ======= ===========================================================
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| 42 | nowc Don't map the framebuffer write combined. This can be used
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| 43 | to workaround side-effects and slowdowns on other CPU cores
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| 44 | when large amounts of console data are written.
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| 45 | ======= ===========================================================
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| 46 |
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| 47 | Options for GOP displays:
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| 48 |
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| 49 | mode=n
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| 50 | The EFI stub will set the mode of the display to mode number n if
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| 51 | possible.
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| 52 |
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| 53 | <xres>x<yres>[-(rgb|bgr|<bpp>)]
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| 54 | The EFI stub will search for a display mode that matches the specified
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| 55 | horizontal and vertical resolution, and optionally bit depth, and set
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| 56 | the mode of the display to it if one is found. The bit depth can either
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| 57 | "rgb" or "bgr" to match specifically those pixel formats, or a number
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| 58 | for a mode with matching bits per pixel.
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| 59 |
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| 60 | auto
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| 61 | The EFI stub will choose the mode with the highest resolution (product
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| 62 | of horizontal and vertical resolution). If there are multiple modes
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| 63 | with the highest resolution, it will choose one with the highest color
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| 64 | depth.
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| 65 |
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| 66 | list
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| 67 | The EFI stub will list out all the display modes that are available. A
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| 68 | specific mode can then be chosen using one of the above options for the
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| 69 | next boot.
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| 70 |
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| 71 | Edgar Hucek <[email protected]>
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