ESXi 6.7 motherboard serial ports connected to VM Guest loses data and blocks

[Bolleke_70]

We are using a Hypervisor. On that hypervisor we run a windows server 2012.

We want to use the onboard serial ports to communicate to a other system.

during the connection the communication stops. During transmission from the VM the connection freezes.

The serial port blocks and becomes unusable untill restart of the VM.

If we send data to the VM there is no problem. only answers from the VM are slow.

Is there any buffer defined which we can make bigger?

Best Regards,

Dennis

[Bolleke_70 · Accepted solution]

Hello,

the CPU used is a  intel i7 7700 with intel chipset Q170.

As I get further with testing it seems to be in either the Chipset or the CPU. This serie ins't supported by VMware also.

Solved the problem : downgraded the ESXi to 6.5 u2 and now the serial ports on the motherboard work normally.