Problem with I2C

aanistratenko

We had bought 2 PCs from Mouser.

We encountered a problem with one of the PCs - the I2C bus on the HAT connector doesn't function properly with any devices.
The first PCs (PC-1) have no issues in either Standard or Fast mode.

However, PC-2 fails to communicate through the I2C bus when there are multiple devices connected to it. We attempted to change the bus frequency in the BIOS, but the SCL impulses remain corrupted.
At this moment in terminal we have error: i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration.

We conducted tests with various pull-up resistors, ranging from 1K to 10K, but the problem persists regardless of the tolerance.

We performed these tests using both the FSP PMbus Power Supply and our custom motherboard.

We are confident that the issues lie with the hardware components.

BIOS version are same on all PC - 6.3.

OS version are same on all PC - Ubuntu 22.04

Shell output and photos of i2c signals attached in files.