mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 04:34:11 +08:00
35 lines
1.4 KiB
Plaintext
35 lines
1.4 KiB
Plaintext
|
Linux Braille Console
|
||
|
|
|
||
|
|
To get early boot messages on a braille device (before userspace screen
|
||
|
|
readers can start), you first need to compile the support for the usual serial
|
||
|
|
console (see serial-console.txt), and for braille device (in Device Drivers -
|
||
|
|
Accessibility).
|
||
|
|
|
||
|
|
Then you need to specify a console=brl, option on the kernel command line, the
|
||
|
|
format is:
|
||
|
|
|
||
|
|
console=brl,serial_options...
|
||
|
|
|
||
|
|
where serial_options... are the same as described in serial-console.txt
|
||
|
|
|
||
|
|
So for instance you can use console=brl,ttyS0 if the braille device is connected
|
||
|
|
to the first serial port, and console=brl,ttyS0,115200 to override the baud rate
|
||
|
|
to 115200, etc.
|
||
|
|
|
||
|
|
By default, the braille device will just show the last kernel message (console
|
||
|
|
mode). To review previous messages, press the Insert key to switch to the VT
|
||
|
|
review mode. In review mode, the arrow keys permit to browse in the VT content,
|
||
|
|
page up/down keys go at the top/bottom of the screen, and the home key goes back
|
||
|
|
to the cursor, hence providing very basic screen reviewing facility.
|
||
|
|
|
||
|
|
Sound feedback can be obtained by adding the braille_console.sound=1 kernel
|
||
|
|
parameter.
|
||
|
|
|
||
|
|
For simplicity, only one braille console can be enabled, other uses of
|
||
|
|
console=brl,... will be discarded. Also note that it does not interfere with
|
||
|
|
the console selection mecanism described in serial-console.txt
|
||
|
|
|
||
|
|
For now, only the VisioBraille device is supported.
|
||
|
|
|
||
|
|
Samuel Thibault <samuel.thibault@ens-lyon.org>
|