Mesa 7i96 Installing to Run

I'm taking power from USB port of the same laptop i'm using for control. Power should be stable.

I should note that laptops are never recommended for LinuxCNC
as they often have power management hardware/ firmware that
cannot be disabled and adversely affects latency.
 

I found those 4 green LEDs are showing packet sending events in 4-bit form - CR14 being LSB. At least it looks like this. When the connection is stable CR14 is most dimmed and the rest progressively getting brighter. I used USB-Eth adapter to see what will be the effect on ping and response time lengthened to ca 0.7ms and i could see binary sequence on green LEDs with those long ping times...

Clever indicator:)
But i'm now falling into darkness of sadness as playing with reinstalling the system with some latest kernel looks like hard task to me.

Yes, at home i have old optiplex 620 for that and some other units waiting. The thing is i'm offshore and laptop is the only thing i have. Wait a minute! I also have RP Pi4 (2GB or 4GB) here. I saw somewhere Linuxcnc can run on RB Pi4. But the how to control RB headless if Eth will be occupied by Mesa? I have USB-Eth adapter to try.

If you are just testing (which may be all a laptop is good for),
you could try a say 5 ms servo thread

I did not see what the NIC was in your PC.

Re the Realteks, the best practice is to install the R8168-dkms driver if it is applicable for your hardware. This is discussed in the getting linuxcnc docs in 2.9
Ref: linuxcnc.org/docs/2.9/html/getting-start...etting-linuxcnc.html
Beyond that, installing a later kernel aslo fixes a lot of issues. 

A couple of recent developments.
1. There is now  Energy Efficient Ethernet (EEE which is dropping network connections if enabled. We need to explore how to fix that.
2 A recent patch on the RT kernel was addresses at fixing bugs in Lazy Preemption. From memory, it was added back around kernel 5.09. This I always thought could be the issue with the error finishing  read problem that  commenced with the Bullseye 5.10 kernel. I will see if I can find out a bit more on this.
 

Appreciate it.
I'll try 5ms. From real life experience - what would be the max acceptable servo period time for regular cnc router? Maybe 5ms is fine? What is one plan to use threading on the lathe or hard tapping on the milling machine? Will spindle sync with axes motion be maintained? After all, home grew machines are not super fast. I have a set of those aliexpress integrated AC servo motors for tests and also some made-myself DC servo drives (based on old UHU servo) as well as aliexpress 230VAC powered AC servo packs with 17-bit encoders. I need to make them woking with Mesa for my homemade builds.

5 ms is pretty slow for a router, The issue is mainly the size of velocity
steps during acceleration. It can be made to work but will limit
maximum acceleration

Ok, i can see what you mean Rod:
 

Update: the tests i've done today:
- isolated CPUs in grb-customizer (quiet isolcpus=2,3)
- checked NIC
- checked NIC driver i have: RTL8169
- installed different driver: RTL8168
- checked ping times after driver change - worsen literally 10 times! 1.6ms
- purged RTL8168 and went back to RTL78169
 
- checked ping times 0.14ms
- Mesa problem is still there
- installed kernel 6.3 as per here:
 
 
- checked things
 
- problem still there
 
...even on servo thread period 2ms:/


Then, i don't know what i did, i thought i only changed period to 5ms i got this when loading linuxcnc:
 
and red LED came on immediately when linuxcnc started but i got no reading error and i could move the tool on the screen (using arrows). However XYZ position feedback numbers were jerky. In addition i can see 4 green LEDs blinking as the packets are transmitted/received.

So i've changed servo thread period back to 2ms. And restored previous situation so no red LED at the beginning, no jerky numbers however error finishing read is still there.

I give up.