linux/Documentation/fb/intelfb.rst
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   1=============================================================
   2Intel 830M/845G/852GM/855GM/865G/915G/945G Framebuffer driver
   3=============================================================
   4
   5A. Introduction
   6===============
   7
   8This is a framebuffer driver for various Intel 8xx/9xx compatible
   9graphics devices.  These would include:
  10
  11        - Intel 830M
  12        - Intel 845G
  13        - Intel 852GM
  14        - Intel 855GM
  15        - Intel 865G
  16        - Intel 915G
  17        - Intel 915GM
  18        - Intel 945G
  19        - Intel 945GM
  20        - Intel 945GME
  21        - Intel 965G
  22        - Intel 965GM
  23
  24B.  List of available options
  25=============================
  26
  27   a. "video=intelfb"
  28        enables the intelfb driver
  29
  30        Recommendation: required
  31
  32   b. "mode=<xres>x<yres>[-<bpp>][@<refresh>]"
  33        select mode
  34
  35        Recommendation: user preference
  36        (default = 1024x768-32@70)
  37
  38   c. "vram=<value>"
  39        select amount of system RAM in MB to allocate for the video memory
  40        if not enough RAM was already allocated by the BIOS.
  41
  42        Recommendation: 1 - 4 MB.
  43        (default = 4 MB)
  44
  45   d. "voffset=<value>"
  46        select at what offset in MB of the logical memory to allocate the
  47        framebuffer memory.  The intent is to avoid the memory blocks
  48        used by standard graphics applications (XFree86). Depending on your
  49        usage, adjust the value up or down, (0 for maximum usage, 63/127 MB
  50        for the least amount).  Note, an arbitrary setting may conflict
  51        with XFree86.
  52
  53        Recommendation: do not set
  54        (default = 48 MB)
  55
  56   e. "accel"
  57        enable text acceleration.  This can be enabled/reenabled anytime
  58        by using 'fbset -accel true/false'.
  59
  60        Recommendation: enable
  61        (default = set)
  62
  63   f. "hwcursor"
  64        enable cursor acceleration.
  65
  66        Recommendation: enable
  67        (default = set)
  68
  69   g. "mtrr"
  70        enable MTRR.  This allows data transfers to the framebuffer memory
  71        to occur in bursts which can significantly increase performance.
  72        Not very helpful with the intel chips because of 'shared memory'.
  73
  74        Recommendation: set
  75        (default = set)
  76
  77   h. "fixed"
  78        disable mode switching.
  79
  80        Recommendation: do not set
  81        (default = not set)
  82
  83   The binary parameters can be unset with a "no" prefix, example "noaccel".
  84   The default parameter (not named) is the mode.
  85
  86C. Kernel booting
  87=================
  88
  89Separate each option/option-pair by commas (,) and the option from its value
  90with an equals sign (=) as in the following::
  91
  92        video=intelfb:option1,option2=value2
  93
  94Sample Usage
  95------------
  96
  97In /etc/lilo.conf, add the line::
  98
  99        append="video=intelfb:mode=800x600-32@75,accel,hwcursor,vram=8"
 100
 101This will initialize the framebuffer to 800x600 at 32bpp and 75Hz. The
 102framebuffer will use 8 MB of System RAM. hw acceleration of text and cursor
 103will be enabled.
 104
 105Remarks
 106-------
 107
 108If setting this parameter doesn't work (you stay in a 80x25 text-mode),
 109you might need to set the "vga=<mode>" parameter too - see vesafb.txt
 110in this directory.
 111
 112
 113D.  Module options
 114==================
 115
 116The module parameters are essentially similar to the kernel
 117parameters. The main difference is that you need to include a Boolean value
 118(1 for TRUE, and 0 for FALSE) for those options which don't need a value.
 119
 120Example, to enable MTRR, include "mtrr=1".
 121
 122Sample Usage
 123------------
 124
 125Using the same setup as described above, load the module like this::
 126
 127        modprobe intelfb mode=800x600-32@75 vram=8 accel=1 hwcursor=1
 128
 129Or just add the following to a configuration file in /etc/modprobe.d/::
 130
 131        options intelfb mode=800x600-32@75 vram=8 accel=1 hwcursor=1
 132
 133and just do a::
 134
 135        modprobe intelfb
 136
 137
 138E.  Acknowledgment:
 139===================
 140
 141        1.  Geert Uytterhoeven - his excellent howto and the virtual
 142            framebuffer driver code made this possible.
 143
 144        2.  Jeff Hartmann for his agpgart code.
 145
 146        3.  David Dawes for his original kernel 2.4 code.
 147
 148        4.  The X developers.  Insights were provided just by reading the
 149            XFree86 source code.
 150
 151        5.  Antonino A. Daplas for his inspiring i810fb driver.
 152
 153        6.  Andrew Morton for his kernel patches maintenance.
 154
 155Sylvain
 156