I2C Bus Lock Prevention HLD #1907
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It is known that the i2c bus will not work if there is an i2c device unexpectedly pulls i2c's SDA signal low. A detailed discussion of the I2C bus lock problem can be found at https://community.nxp.com/t5/i-MX-Processors/I2C-reset/m-p/253182.
We have observed that some transceivers inserted on the switch work fine at first, but after a while run into the i2c bus lock problem. The only way to recover from the i2c bus lock state is to remove the faulty transceiver. However, there is no easy way to identify which transceiver is the one that is locking the i2c bus. The brute force method is to unplug the inserted transceivers one by one to find out. Once the faulty transceiver has been removed, the i2c-related error messages will no longer appear in the syslog.
The purpose of the HLD is to mitigate the aforementioned i2c problem caused by the transceiver. This HLD explains the design to monitor the i2c bus health status in the background, the way to restore the i2c bus by detecting the faulty i2c device, isolating the detected faulty device, and restoring the i2c bus to normal status.