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