mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-29 23:46:41 +07:00
f7511d5f66
This adds a minimalistic braille screen reader support. This is meant to be used by blind people e.g. on boot failures or when / cannot be mounted etc and thus the userland screen readers can not work. [akpm@linux-foundation.org: fix exports] Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Jiri Kosina <jikos@jikos.cz> Cc: Dmitry Torokhov <dtor@mail.ru> Acked-by: Alan Cox <alan@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
|