Root/Documentation/fb/sisfb.txt

1
2What is sisfb?
3==============
4
5sisfb is a framebuffer device driver for SiS (Silicon Integrated Systems)
6graphics chips. Supported are:
7
8- SiS 300 series: SiS 300/305, 540, 630(S), 730(S)
9- SiS 315 series: SiS 315/H/PRO, 55x, (M)65x, 740, (M)661(F/M)X, (M)741(GX)
10- SiS 330 series: SiS 330 ("Xabre"), (M)760
11
12
13Why do I need a framebuffer driver?
14===================================
15
16sisfb is eg. useful if you want a high-resolution text console. Besides that,
17sisfb is required to run DirectFB (which comes with an additional, dedicated
18driver for the 315 series).
19
20On the 300 series, sisfb on kernels older than 2.6.3 furthermore plays an
21important role in connection with DRM/DRI: Sisfb manages the memory heap
22used by DRM/DRI for 3D texture and other data. This memory management is
23required for using DRI/DRM.
24
25Kernels >= around 2.6.3 do not need sisfb any longer for DRI/DRM memory
26management. The SiS DRM driver has been updated and features a memory manager
27of its own (which will be used if sisfb is not compiled). So unless you want
28a graphical console, you don't need sisfb on kernels >=2.6.3.
29
30Sidenote: Since this seems to be a commonly made mistake: sisfb and vesafb
31cannot be active at the same time! Do only select one of them in your kernel
32configuration.
33
34
35How are parameters passed to sisfb?
36===================================
37
38Well, it depends: If compiled statically into the kernel, use lilo's append
39statement to add the parameters to the kernel command line. Please see lilo's
40(or GRUB's) documentation for more information. If sisfb is a kernel module,
41parameters are given with the modprobe (or insmod) command.
42
43Example for sisfb as part of the static kernel: Add the following line to your
44lilo.conf:
45
46     append="video=sisfb:mode:1024x768x16,mem:12288,rate:75"
47
48Example for sisfb as a module: Start sisfb by typing
49
50     modprobe sisfb mode=1024x768x16 rate=75 mem=12288
51
52A common mistake is that folks use a wrong parameter format when using the
53driver compiled into the kernel. Please note: If compiled into the kernel,
54the parameter format is video=sisfb:mode:none or video=sisfb:mode:1024x768x16
55(or whatever mode you want to use, alternatively using any other format
56described above or the vesa keyword instead of mode). If compiled as a module,
57the parameter format reads mode=none or mode=1024x768x16 (or whatever mode you
58want to use). Using a "=" for a ":" (and vice versa) is a huge difference!
59Additionally: If you give more than one argument to the in-kernel sisfb, the
60arguments are separated with ",". For example:
61
62   video=sisfb:mode:1024x768x16,rate:75,mem:12288
63
64
65How do I use it?
66================
67
68Preface statement: This file only covers very little of the driver's
69capabilities and features. Please refer to the author's and maintainer's
70website at http://www.winischhofer.net/linuxsisvga.shtml for more
71information. Additionally, "modinfo sisfb" gives an overview over all
72supported options including some explanation.
73
74The desired display mode can be specified using the keyword "mode" with
75a parameter in one of the following formats:
76  - XxYxDepth or
77  - XxY-Depth or
78  - XxY-Depth@Rate or
79  - XxY
80  - or simply use the VESA mode number in hexadecimal or decimal.
81
82For example: 1024x768x16, 1024x768-16@75, 1280x1024-16. If no depth is
83specified, it defaults to 8. If no rate is given, it defaults to 60Hz. Depth 32
84means 24bit color depth (but 32 bit framebuffer depth, which is not relevant
85to the user).
86
87Additionally, sisfb understands the keyword "vesa" followed by a VESA mode
88number in decimal or hexadecimal. For example: vesa=791 or vesa=0x117. Please
89use either "mode" or "vesa" but not both.
90
91Linux 2.4 only: If no mode is given, sisfb defaults to "no mode" (mode=none) if
92compiled as a module; if sisfb is statically compiled into the kernel, it
93defaults to 800x600x8 unless CRT2 type is LCD, in which case the LCD's native
94resolution is used. If you want to switch to a different mode, use the fbset
95shell command.
96
97Linux 2.6 only: If no mode is given, sisfb defaults to 800x600x8 unless CRT2
98type is LCD, in which case it defaults to the LCD's native resolution. If
99you want to switch to another mode, use the stty shell command.
100
101You should compile in both vgacon (to boot if you remove you SiS card from
102your system) and sisfb (for graphics mode). Under Linux 2.6, also "Framebuffer
103console support" (fbcon) is needed for a graphical console.
104
105You should *not* compile-in vesafb. And please do not use the "vga=" keyword
106in lilo's or grub's configuration file; mode selection is done using the
107"mode" or "vesa" keywords as a parameter. See above and below.
108
109
110X11
111===
112
113If using XFree86 or X.org, it is recommended that you don't use the "fbdev"
114driver but the dedicated "sis" X driver. The "sis" X driver and sisfb are
115developed by the same person (Thomas Winischhofer) and cooperate well with
116each other.
117
118
119SVGALib
120=======
121
122SVGALib, if directly accessing the hardware, never restores the screen
123correctly, especially on laptops or if the output devices are LCD or TV.
124Therefore, use the chipset "FBDEV" in SVGALib configuration. This will make
125SVGALib use the framebuffer device for mode switches and restoration.
126
127
128Configuration
129=============
130
131(Some) accepted options:
132
133off - Disable sisfb. This option is only understood if sisfb is
134           in-kernel, not a module.
135mem:X - size of memory for the console, rest will be used for DRI/DRM. X
136           is in kilobytes. On 300 series, the default is 4096, 8192 or
137       16384 (each in kilobyte) depending on how much video ram the card
138           has. On 315/330 series, the default is the maximum available ram
139       (since DRI/DRM is not supported for these chipsets).
140noaccel - do not use 2D acceleration engine. (Default: use acceleration)
141noypan - disable y-panning and scroll by redrawing the entire screen.
142           This is much slower than y-panning. (Default: use y-panning)
143vesa:X - selects startup videomode. X is number from 0 to 0x1FF and
144           represents the VESA mode number (can be given in decimal or
145       hexadecimal form, the latter prefixed with "0x").
146mode:X - selects startup videomode. Please see above for the format of
147           "X".
148
149Boolean options such as "noaccel" or "noypan" are to be given without a
150parameter if sisfb is in-kernel (for example "video=sisfb:noypan). If
151sisfb is a module, these are to be set to 1 (for example "modprobe sisfb
152noypan=1").
153
154--
155Thomas Winischhofer <thomas@winischhofer.net>
156May 27, 2004
157
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