Documentation/fb/intelfb.txt

   1 Intel 830M/845G/852GM/855GM/865G/915G/945G Framebuffer driver
   2 ================================================================
   3
   4 A. Introduction
   5         This is a framebuffer driver for various Intel 8xx/9xx compatible
   6 graphics devices.  These would include:
   7
   8         Intel 830M
   9         Intel 845G
  10         Intel 852GM
  11         Intel 855GM
  12         Intel 865G
  13         Intel 915G
  14         Intel 915GM
  15         Intel 945G
  16         Intel 945GM
  17         Intel 965G
  18         Intel 965GM
  19
  20 B.  List of available options
  21
  22    a. "video=intelfb"
  23         enables the intelfb driver
  24
  25         Recommendation: required
  26
  27    b. "mode=<xres>x<yres>[-<bpp>][@<refresh>]"
  28         select mode
  29
  30         Recommendation: user preference
  31         (default = 1024x768-32@70)
  32
  33    c. "vram=<value>"
  34         select amount of system RAM in MB to allocate for the video memory
  35         if not enough RAM was already allocated by the BIOS.
  36
  37         Recommendation: 1 - 4 MB.
  38         (default = 4 MB)
  39
  40    d. "voffset=<value>"
  41         select at what offset in MB of the logical memory to allocate the
  42         framebuffer memory.  The intent is to avoid the memory blocks
  43         used by standard graphics applications (XFree86). Depending on your
  44         usage, adjust the value up or down, (0 for maximum usage, 63/127 MB
  45         for the least amount).  Note, an arbitrary setting may conflict
  46         with XFree86.
  47
  48         Recommendation: do not set
  49         (default = 48 MB)
  50
  51    e. "accel"
  52         enable text acceleration.  This can be enabled/reenabled anytime
  53         by using 'fbset -accel true/false'.
  54
  55         Recommendation: enable
  56         (default = set)
  57
  58    f. "hwcursor"
  59         enable cursor acceleration.
  60
  61         Recommendation: enable
  62         (default = set)
  63
  64    g. "mtrr"
  65         enable MTRR.  This allows data transfers to the framebuffer memory
  66         to occur in bursts which can significantly increase performance.
  67         Not very helpful with the intel chips because of 'shared memory'.
  68
  69         Recommendation: set
  70         (default = set)
  71
  72    h. "fixed"
  73         disable mode switching.
  74
  75         Recommendation: do not set
  76         (default = not set)
  77
  78    The binary parameters can be unset with a "no" prefix, example "noaccel".
  79    The default parameter (not named) is the mode.
  80
  81 C. Kernel booting
  82
  83 Separate each option/option-pair by commas (,) and the option from its value
  84 with an equals sign (=) as in the following:
  85
  86 video=intelfb:option1,option2=value2
  87
  88 Sample Usage
  89 ------------
  90
  91 In /etc/lilo.conf, add the line:
  92
  93 append="video=intelfb:mode=800x600-32@75,accel,hwcursor,vram=8"
  94
  95 This will initialize the framebuffer to 800x600 at 32bpp and 75Hz. The
  96 framebuffer will use 8 MB of System RAM. hw acceleration of text and cursor
  97 will be enabled.
  98
  99 Remarks
 100 -------
 101
 102 If setting this parameter doesn't work (you stay in a 80x25 text-mode),
 103 you might need to set the "vga=<mode>" parameter too - see vesafb.txt
 104 in this directory.
 105
 106
 107 D.  Module options
 108
 109         The module parameters are essentially similar to the kernel
 110 parameters. The main difference is that you need to include a Boolean value
 111 (1 for TRUE, and 0 for FALSE) for those options which don't need a value.
 112
 113 Example, to enable MTRR, include "mtrr=1".
 114
 115 Sample Usage
 116 ------------
 117
 118 Using the same setup as described above, load the module like this:
 119
 120         modprobe intelfb mode=800x600-32@75 vram=8 accel=1 hwcursor=1
 121
 122 Or just add the following to /etc/modprobe.conf
 123
 124         options intelfb mode=800x600-32@75 vram=8 accel=1 hwcursor=1
 125
 126 and just do a
 127
 128         modprobe intelfb
 129
 130
 131 E.  Acknowledgment:
 132
 133         1.  Geert Uytterhoeven - his excellent howto and the virtual
 134                                  framebuffer driver code made this possible.
 135
 136         2.  Jeff Hartmann for his agpgart code.
 137
 138         3.  David Dawes for his original kernel 2.4 code.
 139
 140         4.  The X developers.  Insights were provided just by reading the
 141             XFree86 source code.
 142
 143         5.  Antonino A. Daplas for his inspiring i810fb driver.
 144
 145         6.  Andrew Morton for his kernel patches maintenance.
 146
 147 ###########################
 148 Sylvain