RE: ATF support for r8152 driver

RE: ATF support for r8152 driver

[Hayes Wang]

Максим <rizlirizlirizli@gmail.com> 
[...]
> Hello,
> I'm using a USB Type-C to SFP adapter based on the RTL8153 chip (driver: r8152) on Linux. The adapter has an SFP cage and I'm trying to read the module's DDM/DOM diagnostics (TX/RX optical power, bias current, temperature, voltage) via the standard ethtool interface.
> Device info:
> lsusb: Bus 003 Device 005: ID 0bda:8153 Realtek Semiconductor Corp. RTL8153 Gigabit Ethernet Adapter
> Interface name: enp0s20f0u3
> Driver version: r8152 v1.12.13 (vermagic: 6.12.101+deb13-amd64 SMP preempt mod_unload modversions)
> What I observe:
> ethtool -m enp0s20f0u3
> Netlink error: Operation not supported
> Checking dmesg immediately after the call shows no driver activity at all related to this request — the call appears to be rejected before any USB transaction is attempted, which suggests get_module_eeprom, get_module_info is simply not implemented in struct ethtool_ops for this driver.
> I noticed that get_module support was recently added for RTL8127 (a different chip, r8169 driver) — the patch "r8169: implement get_module functions for rtl8127atf" (Fabio Baltieri, April 2026). I'm writing to ask:
> Is there any plan to implement get_module_eeprom, get_module_info (or the newer get_module_eeprom_by_page) for RTL8153 in the r8152 driver?
> Does the RTL8153 hardware even expose the SFP cage's I2C/TWSI lines to the host in a way that would make this feasible, or are they only used internally by the chip (e.g., shared with the chip's own EEPROM interface)?
> Is there any existing internal Realtek tool (even unofficial/Windows-only) used for production testing of RTL8153-based SFP adapters that reads DDM data, which could inform an implementation?
> Happy to test any patch or provide further debugging information (USB captures, register dumps, etc.) if that would help.

To my knowledge, the RTL8152, RTL8153, RTL8156, and RTL8157 do not provide a host-accessible interface for accessing the SFP module's I2C bus.
Therefore, support for reading the SFP EEPROM or DDM/DOM diagnostics cannot be added by modifying the driver alone.

Best Regards,
Hayes