diff options
Diffstat (limited to 'Documentation/braille-console.txt')
-rw-r--r-- | Documentation/braille-console.txt | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/Documentation/braille-console.txt b/Documentation/braille-console.txt new file mode 100644 index 000000000000..000b0fbdc105 --- /dev/null +++ b/Documentation/braille-console.txt | |||
@@ -0,0 +1,34 @@ | |||
1 | Linux Braille Console | ||
2 | |||
3 | To get early boot messages on a braille device (before userspace screen | ||
4 | readers can start), you first need to compile the support for the usual serial | ||
5 | console (see serial-console.txt), and for braille device (in Device Drivers - | ||
6 | Accessibility). | ||
7 | |||
8 | Then you need to specify a console=brl, option on the kernel command line, the | ||
9 | format is: | ||
10 | |||
11 | console=brl,serial_options... | ||
12 | |||
13 | where serial_options... are the same as described in serial-console.txt | ||
14 | |||
15 | So for instance you can use console=brl,ttyS0 if the braille device is connected | ||
16 | to the first serial port, and console=brl,ttyS0,115200 to override the baud rate | ||
17 | to 115200, etc. | ||
18 | |||
19 | By default, the braille device will just show the last kernel message (console | ||
20 | mode). To review previous messages, press the Insert key to switch to the VT | ||
21 | review mode. In review mode, the arrow keys permit to browse in the VT content, | ||
22 | page up/down keys go at the top/bottom of the screen, and the home key goes back | ||
23 | to the cursor, hence providing very basic screen reviewing facility. | ||
24 | |||
25 | Sound feedback can be obtained by adding the braille_console.sound=1 kernel | ||
26 | parameter. | ||
27 | |||
28 | For simplicity, only one braille console can be enabled, other uses of | ||
29 | console=brl,... will be discarded. Also note that it does not interfere with | ||
30 | the console selection mecanism described in serial-console.txt | ||
31 | |||
32 | For now, only the VisioBraille device is supported. | ||
33 | |||
34 | Samuel Thibault <samuel.thibault@ens-lyon.org> | ||