Root/Documentation/fb/intelfb.txt

1Intel 830M/845G/852GM/855GM/865G/915G/945G Framebuffer driver
2================================================================
3
4A. Introduction
5    This is a framebuffer driver for various Intel 8xx/9xx compatible
6graphics 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
21B. 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
82C. Kernel booting
83
84Separate each option/option-pair by commas (,) and the option from its value
85with an equals sign (=) as in the following:
86
87video=intelfb:option1,option2=value2
88
89Sample Usage
90------------
91
92In /etc/lilo.conf, add the line:
93
94append="video=intelfb:mode=800x600-32@75,accel,hwcursor,vram=8"
95
96This will initialize the framebuffer to 800x600 at 32bpp and 75Hz. The
97framebuffer will use 8 MB of System RAM. hw acceleration of text and cursor
98will be enabled.
99
100Remarks
101-------
102
103If setting this parameter doesn't work (you stay in a 80x25 text-mode),
104you might need to set the "vga=<mode>" parameter too - see vesafb.txt
105in this directory.
106
107
108D. Module options
109
110    The module parameters are essentially similar to the kernel
111parameters. 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
114Example, to enable MTRR, include "mtrr=1".
115
116Sample Usage
117------------
118
119Using 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
123Or just add the following to /etc/modprobe.conf
124
125    options intelfb mode=800x600-32@75 vram=8 accel=1 hwcursor=1
126
127and just do a
128
129    modprobe intelfb
130
131
132E. 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###########################
149Sylvain
150

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