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