On Mon, Jun 28, 2021 at 05:12:29PM +0200, Pali Rohár wrote: > Some SFP modules are not detected when i2c-fast-mode is enabled even when > clock-frequency is already set to 100000. The I2C bus violates the timing > specifications when run in fast mode. So disable fast mode on Turris Mox. Yes. SFP module specification is 100kHz max on the I2C bus, which is often forgotten about until someone runs into a problem. Acked-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx> -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!