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author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-09-21 14:51:11 +0200 |
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committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-10-24 12:12:35 +0200 |
commit | 9d85025b0418163fae079c9ba8f8445212de8568 (patch) | |
tree | 4629e2dedf4a9ed45a6855c129101f9b52138372 /Documentation/admin-guide/braille-console.rst | |
parent | docs-rst: add documents to development-process (diff) | |
download | linux-9d85025b0418163fae079c9ba8f8445212de8568.tar.xz linux-9d85025b0418163fae079c9ba8f8445212de8568.zip |
docs-rst: create an user's manual book
Place README, REPORTING-BUGS, SecurityBugs and kernel-parameters
on an user's manual book.
As we'll be numbering the user's manual, remove the manual
numbering from SecurityBugs.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'Documentation/admin-guide/braille-console.rst')
-rw-r--r-- | Documentation/admin-guide/braille-console.rst | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/Documentation/admin-guide/braille-console.rst b/Documentation/admin-guide/braille-console.rst new file mode 100644 index 000000000000..fa3702dc04ab --- /dev/null +++ b/Documentation/admin-guide/braille-console.rst @@ -0,0 +1,38 @@ +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/serial-console.txt <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/serial-console.txt <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/serial-console.txt <serial_console>`. + +For now, only the VisioBraille device is supported. + +Samuel Thibault <samuel.thibault@ens-lyon.org> |