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Commit f7511d5f authored by Samuel Thibault's avatar Samuel Thibault Committed by Linus Torvalds
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Basic braille screen reader support 



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: default avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Jiri Kosina <jikos@jikos.cz>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-by: default avatarAlan Cox <alan@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 730f412c

Documentation/braille-console.txt

0 → 100644
+34 −0
Original line number Diff line number Diff line 
                       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>

Documentation/kernel-parameters.txt

+5 −0
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@@ -496,6 +496,11 @@ and is between 256 and 4096 characters. It is defined in the file 
			switching to the matching ttyS device later.  The

			options are the same as for ttyS, above.



                If the device connected to the port is not a TTY but a braille

                device, prepend "brl," before the device type, for instance

			console=brl,ttyS0

		For now, only VisioBraille is supported.



	earlycon=	[KNL] Output early console device and options.

		uart[8250],io,<addr>[,options]

		uart[8250],mmio,<addr>[,options]

arch/powerpc/kernel/ppc_ksyms.c

+0 −3
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@@ -133,9 +133,6 @@ EXPORT_SYMBOL(adb_try_handler_change); 
EXPORT_SYMBOL(cuda_request);

EXPORT_SYMBOL(cuda_poll);

#endif /* CONFIG_ADB_CUDA */

#ifdef CONFIG_VT

EXPORT_SYMBOL(kd_mksound);

#endif

EXPORT_SYMBOL(to_tm);



#ifdef CONFIG_PPC32

arch/ppc/kernel/ppc_ksyms.c

+0 −3
Original line number Diff line number Diff line
@@ -183,9 +183,6 @@ EXPORT_SYMBOL(cuda_poll); 
#if defined(CONFIG_BOOTX_TEXT)

EXPORT_SYMBOL(btext_update_display);

#endif

#ifdef CONFIG_VT

EXPORT_SYMBOL(kd_mksound);

#endif

EXPORT_SYMBOL(to_tm);



EXPORT_SYMBOL(pm_power_off);

drivers/Kconfig

+2 −0
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@@ -84,6 +84,8 @@ source "drivers/memstick/Kconfig" 


source "drivers/leds/Kconfig"



source "drivers/accessibility/Kconfig"



source "drivers/infiniband/Kconfig"



source "drivers/edac/Kconfig"