Doug / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit 2d9d2fdfae4cf7fda90178a9daf0f8f750043ae8

Authored by Paul Menzel
Committed by Linus Torvalds
1 parent 27b7f2e3b5
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

Documentation/fb/vesafb.txt: fix typo 

Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Cc: Gerd Knorr <kraxel@goldbach.in-berlin.de>
Cc: Nico Schmoigl <schmoigl@rumms.uni-mannheim.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 1 additions and 1 deletions Inline Diff

Documentation/fb/vesafb.txt
Diff comments   View file @ 2d9d2fd
1 1
2 What is vesafb? 2 What is vesafb?
3 =============== 3 ===============
4 4
5 This is a generic driver for a graphic framebuffer on intel boxes. 5 This is a generic driver for a graphic framebuffer on intel boxes.
6 6
7 The idea is simple: Turn on graphics mode at boot time with the help 7 The idea is simple: Turn on graphics mode at boot time with the help
8 of the BIOS, and use this as framebuffer device /dev/fb0, like the m68k 8 of the BIOS, and use this as framebuffer device /dev/fb0, like the m68k
9 (and other) ports do. 9 (and other) ports do.
10 10
11 This means we decide at boot time whenever we want to run in text or 11 This means we decide at boot time whenever we want to run in text or
12 graphics mode. Switching mode later on (in protected mode) is 12 graphics mode. Switching mode later on (in protected mode) is
13 impossible; BIOS calls work in real mode only. VESA BIOS Extensions 13 impossible; BIOS calls work in real mode only. VESA BIOS Extensions
14 Version 2.0 are required, because we need a linear frame buffer. 14 Version 2.0 are required, because we need a linear frame buffer.
15 15
16 Advantages: 16 Advantages:
17 17
18 * It provides a nice large console (128 cols + 48 lines with 1024x768) 18 * It provides a nice large console (128 cols + 48 lines with 1024x768)
19 without using tiny, unreadable fonts. 19 without using tiny, unreadable fonts.
20 * You can run XF68_FBDev on top of /dev/fb0 (=> non-accelerated X11 20 * You can run XF68_FBDev on top of /dev/fb0 (=> non-accelerated X11
21 support for every VBE 2.0 compliant graphics board). 21 support for every VBE 2.0 compliant graphics board).
22 * Most important: boot logo :-) 22 * Most important: boot logo :-)
23 23
24 Disadvantages: 24 Disadvantages:
25 25
26 * graphic mode is slower than text mode... 26 * graphic mode is slower than text mode...
27 27
28 28
29 How to use it? 29 How to use it?
30 ============== 30 ==============
31 31
32 Switching modes is done using the vga=... boot parameter. Read 32 Switching modes is done using the vga=... boot parameter. Read
33 Documentation/svga.txt for details. 33 Documentation/svga.txt for details.
34 34
35 You should compile in both vgacon (for text mode) and vesafb (for 35 You should compile in both vgacon (for text mode) and vesafb (for
36 graphics mode). Which of them takes over the console depends on 36 graphics mode). Which of them takes over the console depends on
37 whenever the specified mode is text or graphics. 37 whenever the specified mode is text or graphics.
38 38
39 The graphic modes are NOT in the list which you get if you boot with 39 The graphic modes are NOT in the list which you get if you boot with
40 vga=ask and hit return. The mode you wish to use is derived from the 40 vga=ask and hit return. The mode you wish to use is derived from the
41 VESA mode number. Here are those VESA mode numbers: 41 VESA mode number. Here are those VESA mode numbers:
42 42
43 | 640x480 800x600 1024x768 1280x1024 43 | 640x480 800x600 1024x768 1280x1024
44 ----+------------------------------------- 44 ----+-------------------------------------
45 256 | 0x101 0x103 0x105 0x107 45 256 | 0x101 0x103 0x105 0x107
46 32k | 0x110 0x113 0x116 0x119 46 32k | 0x110 0x113 0x116 0x119
47 64k | 0x111 0x114 0x117 0x11A 47 64k | 0x111 0x114 0x117 0x11A
48 16M | 0x112 0x115 0x118 0x11B 48 16M | 0x112 0x115 0x118 0x11B
49 49
50 The video mode number of the Linux kernel is the VESA mode number plus 50 The video mode number of the Linux kernel is the VESA mode number plus
51 0x200. 51 0x200.
52 52
53 Linux_kernel_mode_number = VESA_mode_number + 0x200 53 Linux_kernel_mode_number = VESA_mode_number + 0x200
54 54
55 So the table for the Kernel mode numbers are: 55 So the table for the Kernel mode numbers are:
56 56
57 | 640x480 800x600 1024x768 1280x1024 57 | 640x480 800x600 1024x768 1280x1024
58 ----+------------------------------------- 58 ----+-------------------------------------
59 256 | 0x301 0x303 0x305 0x307 59 256 | 0x301 0x303 0x305 0x307
60 32k | 0x310 0x313 0x316 0x319 60 32k | 0x310 0x313 0x316 0x319
61 64k | 0x311 0x314 0x317 0x31A 61 64k | 0x311 0x314 0x317 0x31A
62 16M | 0x312 0x315 0x318 0x31B 62 16M | 0x312 0x315 0x318 0x31B
63 63
64 To enable one of those modes you have to specify "vga=ask" in the 64 To enable one of those modes you have to specify "vga=ask" in the
65 lilo.conf file and rerun LILO. Then you can type in the desired 65 lilo.conf file and rerun LILO. Then you can type in the desired
66 mode at the "vga=ask" prompt. For example if you like to use 66 mode at the "vga=ask" prompt. For example if you like to use
67 1024x768x256 colors you have to say "305" at this prompt. 67 1024x768x256 colors you have to say "305" at this prompt.
68 68
69 If this does not work, this might be because your BIOS does not support 69 If this does not work, this might be because your BIOS does not support
70 linear framebuffers or because it does not support this mode at all. 70 linear framebuffers or because it does not support this mode at all.
71 Even if your board does, it might be the BIOS which does not. VESA BIOS 71 Even if your board does, it might be the BIOS which does not. VESA BIOS
72 Extensions v2.0 are required, 1.2 is NOT sufficient. You will get a 72 Extensions v2.0 are required, 1.2 is NOT sufficient. You will get a
73 "bad mode number" message if something goes wrong. 73 "bad mode number" message if something goes wrong.
74 74
75 1. Note: LILO cannot handle hex, for booting directly with 75 1. Note: LILO cannot handle hex, for booting directly with
76 "vga=mode-number" you have to transform the numbers to decimal. 76 "vga=mode-number" you have to transform the numbers to decimal.
77 2. Note: Some newer versions of LILO appear to work with those hex values, 77 2. Note: Some newer versions of LILO appear to work with those hex values,
78 if you set the 0x in front of the numbers. 78 if you set the 0x in front of the numbers.
79 79
80 X11 80 X11
81 === 81 ===
82 82
83 XF68_FBDev should work just fine, but it is non-accelerated. Running 83 XF68_FBDev should work just fine, but it is non-accelerated. Running
84 another (accelerated) X-Server like XF86_SVGA might or might not work. 84 another (accelerated) X-Server like XF86_SVGA might or might not work.
85 It depends on X-Server and graphics board. 85 It depends on X-Server and graphics board.
86 86
87 The X-Server must restore the video mode correctly, else you end up 87 The X-Server must restore the video mode correctly, else you end up
88 with a broken console (and vesafb cannot do anything about this). 88 with a broken console (and vesafb cannot do anything about this).
89 89
90 90
91 Refresh rates 91 Refresh rates
92 ============= 92 =============
93 93
94 There is no way to change the vesafb video mode and/or timings after 94 There is no way to change the vesafb video mode and/or timings after
95 booting linux. If you are not happy with the 60 Hz refresh rate, you 95 booting linux. If you are not happy with the 60 Hz refresh rate, you
96 have these options: 96 have these options:
97 97
98 * configure and load the DOS-Tools for your the graphics board (if 98 * configure and load the DOS-Tools for the graphics board (if
99 available) and boot linux with loadlin. 99 available) and boot linux with loadlin.
100 * use a native driver (matroxfb/atyfb) instead if vesafb. If none 100 * use a native driver (matroxfb/atyfb) instead if vesafb. If none
101 is available, write a new one! 101 is available, write a new one!
102 * VBE 3.0 might work too. I have neither a gfx board with VBE 3.0 102 * VBE 3.0 might work too. I have neither a gfx board with VBE 3.0
103 support nor the specs, so I have not checked this yet. 103 support nor the specs, so I have not checked this yet.
104 104
105 105
106 Configuration 106 Configuration
107 ============= 107 =============
108 108
109 The VESA BIOS provides protected mode interface for changing 109 The VESA BIOS provides protected mode interface for changing
110 some parameters. vesafb can use it for palette changes and 110 some parameters. vesafb can use it for palette changes and
111 to pan the display. It is turned off by default because it 111 to pan the display. It is turned off by default because it
112 seems not to work with some BIOS versions, but there are options 112 seems not to work with some BIOS versions, but there are options
113 to turn it on. 113 to turn it on.
114 114
115 You can pass options to vesafb using "video=vesafb:option" on 115 You can pass options to vesafb using "video=vesafb:option" on
116 the kernel command line. Multiple options should be separated 116 the kernel command line. Multiple options should be separated
117 by comma, like this: "video=vesafb:ypan,invers" 117 by comma, like this: "video=vesafb:ypan,invers"
118 118
119 Accepted options: 119 Accepted options:
120 120
121 invers no comment... 121 invers no comment...
122 122
123 ypan enable display panning using the VESA protected mode 123 ypan enable display panning using the VESA protected mode
124 interface. The visible screen is just a window of the 124 interface. The visible screen is just a window of the
125 video memory, console scrolling is done by changing the 125 video memory, console scrolling is done by changing the
126 start of the window. 126 start of the window.
127 pro: * scrolling (fullscreen) is fast, because there is 127 pro: * scrolling (fullscreen) is fast, because there is
128 no need to copy around data. 128 no need to copy around data.
129 * You'll get scrollback (the Shift-PgUp thing), 129 * You'll get scrollback (the Shift-PgUp thing),
130 the video memory can be used as scrollback buffer 130 the video memory can be used as scrollback buffer
131 kontra: * scrolling only parts of the screen causes some 131 kontra: * scrolling only parts of the screen causes some
132 ugly flicker effects (boot logo flickers for 132 ugly flicker effects (boot logo flickers for
133 example). 133 example).
134 134
135 ywrap Same as ypan, but assumes your gfx board can wrap-around 135 ywrap Same as ypan, but assumes your gfx board can wrap-around
136 the video memory (i.e. starts reading from top if it 136 the video memory (i.e. starts reading from top if it
137 reaches the end of video memory). Faster than ypan. 137 reaches the end of video memory). Faster than ypan.
138 138
139 redraw scroll by redrawing the affected part of the screen, this 139 redraw scroll by redrawing the affected part of the screen, this
140 is the safe (and slow) default. 140 is the safe (and slow) default.
141 141
142 142
143 vgapal Use the standard vga registers for palette changes. 143 vgapal Use the standard vga registers for palette changes.
144 This is the default. 144 This is the default.
145 pmipal Use the protected mode interface for palette changes. 145 pmipal Use the protected mode interface for palette changes.
146 146
147 mtrr:n setup memory type range registers for the vesafb framebuffer 147 mtrr:n setup memory type range registers for the vesafb framebuffer
148 where n: 148 where n:
149 0 - disabled (equivalent to nomtrr) (default) 149 0 - disabled (equivalent to nomtrr) (default)
150 1 - uncachable 150 1 - uncachable
151 2 - write-back 151 2 - write-back
152 3 - write-combining 152 3 - write-combining
153 4 - write-through 153 4 - write-through
154 154
155 If you see the following in dmesg, choose the type that matches the 155 If you see the following in dmesg, choose the type that matches the
156 old one. In this example, use "mtrr:2". 156 old one. In this example, use "mtrr:2".
157 ... 157 ...
158 mtrr: type mismatch for e0000000,8000000 old: write-back new: write-combining 158 mtrr: type mismatch for e0000000,8000000 old: write-back new: write-combining
159 ... 159 ...
160 160
161 nomtrr disable mtrr 161 nomtrr disable mtrr
162 162
163 vremap:n 163 vremap:n
164 remap 'n' MiB of video RAM. If 0 or not specified, remap memory 164 remap 'n' MiB of video RAM. If 0 or not specified, remap memory
165 according to video mode. (2.5.66 patch/idea by Antonino Daplas 165 according to video mode. (2.5.66 patch/idea by Antonino Daplas
166 reversed to give override possibility (allocate more fb memory 166 reversed to give override possibility (allocate more fb memory
167 than the kernel would) to 2.4 by tmb@iki.fi) 167 than the kernel would) to 2.4 by tmb@iki.fi)
168 168
169 vtotal:n 169 vtotal:n
170 if the video BIOS of your card incorrectly determines the total 170 if the video BIOS of your card incorrectly determines the total
171 amount of video RAM, use this option to override the BIOS (in MiB). 171 amount of video RAM, use this option to override the BIOS (in MiB).
172 172
173 Have fun! 173 Have fun!
174 174
175 Gerd 175 Gerd
176 176
177 -- 177 --
178 Gerd Knorr <kraxel@goldbach.in-berlin.de> 178 Gerd Knorr <kraxel@goldbach.in-berlin.de>
179 179
180 Minor (mostly typo) changes 180 Minor (mostly typo) changes
181 by Nico Schmoigl <schmoigl@rumms.uni-mannheim.de> 181 by Nico Schmoigl <schmoigl@rumms.uni-mannheim.de>
182 182