Designware I2C Controller: Warning: NACK for slave address...

From: Bjoern A. Zeeb <bzeeb-lists_at_lists.zabbadoz.net>
Date: Fri, 12 Sep 2025 21:32:25 UTC
Hi,

after an update to main (say from beginning of June/July) these started
appearing.  How can one find out what they are supposed to talk to?
This is on an f.w16.

# dmesg -a | grep ig4iic1
ig4iic1: <Designware I2C Controller> iomem 0xfedc5000-0xfedc5fff irq 6 on acpi0
ig4iic1: Controller parameters:
iicbus1: <Philips I2C bus (ACPI-hinted)> on ig4iic1
ig4iic1: message with no data
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c
ig4iic1: Warning: NACK for slave address 0x2c

-- 
Bjoern A. Zeeb                                                     r15:7