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authorRandy Dunlap <rdunlap@infradead.org>2017-11-19 13:02:20 -0500
committerJonathan Corbet <corbet@lwn.net>2017-11-20 12:45:50 -0500
commit0cf9bb67f518f1064ec482b790d51a6e02406cba (patch)
treef748a02ad7846842c5a4edaa068ffc9548efd071
parent80416fb43e14e443dd18bc395167f73dba271748 (diff)
documentation/svga.txt: update outdated file
Drop CONFIG_VIDEO_400_HACK info completely. Drop CONFIG_VIDEO_RETAIN and CONFIG_VIDEO_LOCAL completely. Drop CONFIG_VIDEO_COMPACT and CONFIG_VIDEO_VESA info completely. Drop CONFIG_VIDEO_SVGA info since it has been removed. Drop chapter number & section number references since they are wrong. Drop (bad) ftp URL for 800x600 Thinkpad XF86Config. Rename CONFIG_VIDEO_GFX_HACK to VIDEO_GFX_HACK since it is not a Kconfig symbol. And to match the source code. Build options are controlled by the kernel kconfig utility. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Acked-By: Martin Mares <mj@ucw.cz> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
-rw-r--r--Documentation/svga.txt59
1 files changed, 9 insertions, 50 deletions
diff --git a/Documentation/svga.txt b/Documentation/svga.txt
index 119f1515b1ac..b6c2f9acca92 100644
--- a/Documentation/svga.txt
+++ b/Documentation/svga.txt
@@ -67,8 +67,7 @@ The menu looks like::
67<name-of-detected-video-adapter> tells what video adapter did Linux detect 67<name-of-detected-video-adapter> tells what video adapter did Linux detect
68-- it's either a generic adapter name (MDA, CGA, HGC, EGA, VGA, VESA VGA [a VGA 68-- it's either a generic adapter name (MDA, CGA, HGC, EGA, VGA, VESA VGA [a VGA
69with VESA-compliant BIOS]) or a chipset name (e.g., Trident). Direct detection 69with VESA-compliant BIOS]) or a chipset name (e.g., Trident). Direct detection
70of chipsets is turned off by default (see CONFIG_VIDEO_SVGA in chapter 4 to see 70of chipsets is turned off by default as it's inherently unreliable due to
71how to enable it if you really want) as it's inherently unreliable due to
72absolutely insane PC design. 71absolutely insane PC design.
73 72
74"0 0F00 80x25" means that the first menu item (the menu items are numbered 73"0 0F00 80x25" means that the first menu item (the menu items are numbered
@@ -138,7 +137,7 @@ The ID numbers can be divided to those regions::
138 0x0f05 VGA 80x30 (480 scans, 16-point font) 137 0x0f05 VGA 80x30 (480 scans, 16-point font)
139 0x0f06 VGA 80x34 (480 scans, 14-point font) 138 0x0f06 VGA 80x34 (480 scans, 14-point font)
140 0x0f07 VGA 80x60 (480 scans, 8-point font) 139 0x0f07 VGA 80x60 (480 scans, 8-point font)
141 0x0f08 Graphics hack (see the CONFIG_VIDEO_HACK paragraph below) 140 0x0f08 Graphics hack (see the VIDEO_GFX_HACK paragraph below)
142 141
143 0x1000 to 0x7fff - modes specified by resolution. The code has a "0xRRCC" 142 0x1000 to 0x7fff - modes specified by resolution. The code has a "0xRRCC"
144 form where RR is a number of rows and CC is a number of columns. 143 form where RR is a number of rows and CC is a number of columns.
@@ -160,58 +159,22 @@ end of the display.
160Options 159Options
161~~~~~~~ 160~~~~~~~
162 161
163Some options can be set in the source text (in arch/i386/boot/video.S). 162Build options for arch/x86/boot/* are selected by the kernel kconfig
164All of them are simple #define's -- change them to #undef's when you want to 163utility and the kernel .config file.
165switch them off. Currently supported: 164
166 165VIDEO_GFX_HACK - includes special hack for setting of graphics modes
167CONFIG_VIDEO_SVGA - enables autodetection of SVGA cards. This is switched 166to be used later by special drivers.
168off by default as it's a bit unreliable due to terribly bad PC design. If you
169really want to have the adapter autodetected (maybe in case the ``scan`` feature
170doesn't work on your machine), switch this on and don't cry if the results
171are not completely sane. In case you really need this feature, please drop me
172a mail as I think of removing it some day.
173
174CONFIG_VIDEO_VESA - enables autodetection of VESA modes. If it doesn't work
175on your machine (or displays a "Error: Scanning of VESA modes failed" message),
176you can switch it off and report as a bug.
177
178CONFIG_VIDEO_COMPACT - enables compacting of the video mode list. If there
179are more modes with the same screen size, only the first one is kept (see above
180for more info on mode ordering). However, in very strange cases it's possible
181that the first "version" of the mode doesn't work although some of the others
182do -- in this case turn this switch off to see the rest.
183
184CONFIG_VIDEO_RETAIN - enables retaining of screen contents when switching
185video modes. Works only with some boot loaders which leave enough room for the
186buffer. (If you have old LILO, you can adjust heap_end_ptr and loadflags
187in setup.S, but it's better to upgrade the boot loader...)
188
189CONFIG_VIDEO_LOCAL - enables inclusion of "local modes" in the list. The
190local modes are added automatically to the beginning of the list not depending
191on hardware configuration. The local modes are listed in the source text after
192the "local_mode_table:" line. The comment before this line describes the format
193of the table (which also includes a video card name to be displayed on the
194top of the menu).
195
196CONFIG_VIDEO_400_HACK - force setting of 400 scan lines for standard VGA
197modes. This option is intended to be used on certain buggy BIOSes which draw
198some useless logo using font download and then fail to reset the correct mode.
199Don't use unless needed as it forces resetting the video card.
200
201CONFIG_VIDEO_GFX_HACK - includes special hack for setting of graphics modes
202to be used later by special drivers (e.g., 800x600 on IBM ThinkPad -- see
203ftp://ftp.phys.keio.ac.jp/pub/XFree86/800x600/XF86Configs/XF86Config.IBM_TP560).
204Allows to set _any_ BIOS mode including graphic ones and forcing specific 167Allows to set _any_ BIOS mode including graphic ones and forcing specific
205text screen resolution instead of peeking it from BIOS variables. Don't use 168text screen resolution instead of peeking it from BIOS variables. Don't use
206unless you think you know what you're doing. To activate this setup, use 169unless you think you know what you're doing. To activate this setup, use
207mode number 0x0f08 (see section 3). 170mode number 0x0f08 (see the Mode IDs section above).
208 171
209Still doesn't work? 172Still doesn't work?
210~~~~~~~~~~~~~~~~~~~ 173~~~~~~~~~~~~~~~~~~~
211 174
212When the mode detection doesn't work (e.g., the mode list is incorrect or 175When the mode detection doesn't work (e.g., the mode list is incorrect or
213the machine hangs instead of displaying the menu), try to switch off some of 176the machine hangs instead of displaying the menu), try to switch off some of
214the configuration options listed in section 4. If it fails, you can still use 177the configuration options listed under "Options". If it fails, you can still use
215your kernel with the video mode set directly via the kernel parameter. 178your kernel with the video mode set directly via the kernel parameter.
216 179
217In either case, please send me a bug report containing what _exactly_ 180In either case, please send me a bug report containing what _exactly_
@@ -228,10 +191,6 @@ contains the most common video BIOS bug called "incorrect vertical display
228end setting". Adding 0x8000 to the mode ID might fix the problem. Unfortunately, 191end setting". Adding 0x8000 to the mode ID might fix the problem. Unfortunately,
229this must be done manually -- no autodetection mechanisms are available. 192this must be done manually -- no autodetection mechanisms are available.
230 193
231If you have a VGA card and your display still looks as on EGA, your BIOS
232is probably broken and you need to set the CONFIG_VIDEO_400_HACK switch to
233force setting of the correct mode.
234
235History 194History
236~~~~~~~ 195~~~~~~~
237 196