mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-28 07:04:00 +08:00
8c27ceff36
The previous patch renamed several files that are cross-referenced along the Kernel documentation. Adjust the links to point to the right places. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
39 lines
1.7 KiB
ReStructuredText
39 lines
1.7 KiB
ReStructuredText
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 :ref:`Documentation/admin-guide/serial-console.rst <serial_console>`), and
|
|
for braille device
|
|
(in :menuselection:`Device Drivers --> Accessibility support --> Console on braille device`).
|
|
|
|
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
|
|
:ref:`Documentation/admin-guide/serial-console.rst <serial_console>`.
|
|
|
|
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,
|
|
:kbd:`PAGE-UP`/:kbd:`PAGE-DOWN` keys go at the top/bottom of the screen, and
|
|
the :kbd:`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 mechanism described in
|
|
:ref:`Documentation/admin-guide/serial-console.rst <serial_console>`.
|
|
|
|
For now, only the VisioBraille device is supported.
|
|
|
|
Samuel Thibault <samuel.thibault@ens-lyon.org>
|