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