[BRLTTY] brltty hangs after startup

[Dave Mielke]

[quoted lines by Sébastien Hinderer on 2011/04/07 at 14:39 +0200]

>One thing I noticed, thoug, is that when the device is on-line,
>brltty receives its keypresses, but the braille display does not receive
>the braille window updates sent by brltty. It looks as if something
>makes the communication between PC and braille device work one-way only.
>It is for sure not a hardware issue, since restarting brltty is enough
>to get everything back to normal.

If restarting brltty makes it work correctly then that'd seem to eliminate the 
possibility of tere being a flow control and/or parity problem.

Is there an initial handshake during driver startup, involving data being sent 
from the computer to the device, which must take place? If so, would I be 
correct in assuming that this has actually occurred correctly, implying that 
data transfer from the computer to the device at least started out working?

One possibility, especially being as you're using what's effectively a serial 
port, is that the kernel is doing some probing (perhaps for a mouse) at system 
startup, and that this is interfering with the communication between brltty and 
the device. Logging received bytes at both ends should be able to test for 
this.

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