tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 965G
18 Intel 965GM
19
20B. 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
81C. Kernel booting
82
83Separate each option/option-pair by commas (,) and the option from its value
84with an equals sign (=) as in the following:
85
86video=intelfb:option1,option2=value2
87
88Sample Usage
89------------
90
91In /etc/lilo.conf, add the line:
92
93append="video=intelfb:mode=800x600-32@75,accel,hwcursor,vram=8"
94
95This will initialize the framebuffer to 800x600 at 32bpp and 75Hz. The
96framebuffer will use 8 MB of System RAM. hw acceleration of text and cursor
97will be enabled.
98
99Remarks
100-------
101
102If setting this parameter doesn't work (you stay in a 80x25 text-mode),
103you might need to set the "vga=<mode>" parameter too - see vesafb.txt
104in this directory.
105
106
107D. Module options
108
109 The module parameters are essentially similar to the kernel
110parameters. 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
113Example, to enable MTRR, include "mtrr=1".
114
115Sample Usage
116------------
117
118Using 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
122Or just add the following to /etc/modprobe.conf
123
124 options intelfb mode=800x600-32@75 vram=8 accel=1 hwcursor=1
125
126and just do a
127
128 modprobe intelfb
129
130
131E. 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###########################
148Sylvain