Re: USB-serial adapter suggestions needed

On Sat, Jan 06, 2024 at 11:44:49PM +0000, Marcin Cieslak wrote:
> On Fri, 5 Jan 2024, Mark Millard wrote:
> 
> > I also request to again list the exact content of the two
> > config.txt files --and again every time they are changed during
> > this investigation.
> 
> I second this. There is way too much text in this conversation
> and not enough data. It also does not help if every system is somewhat
> different.

Unfortunately, the systems simply are different. Four Pi2, two Pi3,
one Pi4. I'll try to make the config.txt files on the Pi3s match 
better when the present experiment is complete. The interconnection
of hosts is unique and, apparently, unusual. Not all of that is
relevant, but exatctly what part isn't yet obvious.

> 
> I have skimmed the peripherial documentation for one of the Broadcom
> chips (I think the one from Raspberry Pi 3) and it says that
> the speed of the mini uart depends on the CPU clock frequency.
> 
> I could imagine a situation when mini uart speed changes during
> downlocking the CPU.  There was suggestion to not use mini uart.
> Use the port where the frequency is not changing with the weather.
>

Agreed, and I changed config.txt to set
dtoverly=disable-bt 
on www.zefox.org (the console host) to force use of the PL011. 
It didn't help detectably.
 
> I don't know how smart is the power management with powerd, but
> I could also imagine shutting down peripherials or stopping the UART
> clock as a potential power saving feature, so here you are.

No sign of that, but Mark posited that powerd might be causing
trouble with the terminal server (pelorus in this test). That
looks like a possibility. At the moment pelorus is without 
powerd and it's holding a serial connection to www.zefox.org.

Meanwhile www.zefox.org is running powerd and buildworld
while being a terminal server to a Pi4 named nemesis.zefox.com
That connection has dropped twice so far today. 

It'll be a day or so before buildworld finishes.

Thanks for writing!

bob prohaska