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<p>Hi Dave,</p>
<p><br>
</p>
<p>Thanks your answers, I trying increasing the delay time and
repeat the tests with -d serial:ttyACM0, and
serial:ttyACM0+baud=57600 parameters.</p>
<p>The optional brltty.conf delay time parameter is good idea if you
would like adding this option, because the baud rate possible
adding the serial device with +baud=any correct baud number
prefix.</p>
<p>Longer hard coded delay time value perhaps will be good this usb
serial adapter, but need I think examining for example what
happening if for example the usb serial adapter need 2000 MS delay
time to correct set the baud rate if need perhaps appliing the
+baud=57600 prefix (the purpose is BRLTTY always correct
starting), but for example a general serial adapter perhaps will
be too high this delay with future user experience.</p>
<p>Although, if I calculate correctly, 2000 MS is actually 2
seconds, e.g. 20000 MS would be a very long delay for the user
experience if immediate Braille output is needed e.g. on a
recovery screen (20 seconds for BRLTTY to initialize the display,
set the correct baud rate and start), the values 2000 MS and
20000 MS are only assumptions for an immediate serial connection,
a value of 20000 MS will probably not be needed, e.g. the 2 second
wait time while BRLTTY initializes does not seem like much
compared to the other boot processes, I hope a smaller value will
be enough based on experience. (hopefully).<br>
So, it might really be best in the future if this value could also
be controlled by a configuration setting, e.g. with the setting
name serial_ready_delay.<br>
The default setting could be the value that BRLTTY currently uses
for a traditional serial port communication without the waittime
patch (e.g. for the /dev/ttyS0 device), I don't know what this
exact numerical value is, but I'm sure you know.<br>
We'll see what my tests show with different values and different
variations.<br>
I can't promise the results for today, it depends on how long I
can play through the different possible variations (I want to test
multiple starts and automatic starts just to be safe), but I'll
definitely report back.<br>
By the way:<br>
I start the BRLTTY Braille display manager with a Systemd service,
I probably have -q and --no-daemon specified in the
/etc/default/brltty file on my Debian 12 system.<br>
Do I need to adjust the systemd service file, or is the original
version good?<br>
<br>
Attila<br>
</p>
<div class="moz-cite-prefix">2024. 12. 30. 18:16 keltezéssel, Dave
Mielke írta:<br>
</div>
<blockquote type="cite"
cite="mid:Z3LVc5jjb__p7O6f@beta.private.mielke.cc">
<pre class="moz-quote-pre" wrap="">[quoted lines by Hammer Attila on 2024/12/30 at 17:53 +0100]
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">I think the 1000 or 2000 MS perhaps will be too long wait time. What do you
think?
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
I'd still like to know how high it needs to be to work reliably without hard-coding the baud.
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">If you thinking need more increasing the wait time with larger value from 500
Ms, I will be repeat the test.
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
Yes, I'd appreciate that testing.
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">So, BRLTTY is more time right starting this USB adapter when I using the -d
ttyACM0+baud=57600 option.
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
I think that's because there's a longer delay since that sets the 57600 baud a little bit earlier.
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Normal -d ttyACM0, or -d /dev/ttyACM0 newer automatically changing the baud
rate in adapter side this usb serial adapter my experiences.
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
There are four variants that all mean the very same thing:
serial:ttyACM0, serial:/dev/ttyACM0, ttyACM0, /dev/ttyACM0
This is all for backward compatibility to when brltty only supported serial communication, i.e. the /dev/ absolute path prefix is optional and the serial: communiction method is optional. The correct syntax is serial:ttyACM0.
You asked earlier (but I forgot to quote it) if you can specify the baud parameter in brltty.conf - yes, you can. For example:
braille-device serial:ttyACM0+baud=57600
Since the delay seems to need to be so high, I think I'll probably add another serial device parameter for that.
</pre>
</blockquote>
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