Comment 5 for bug 2069001

Revision history for this message
Leith Bade (ljbade) wrote :

I re-compiled the Ubuntu 6.8 kernel with the Mediatek net module enabled.

However I ran into problems with the MDIO port which was preventing the mt7530-mdio driver from setting up the MT7531 switch chip on the board.

I was seeing errors like:
[ 17.353755] mt7530-mdio mdio-bus:1f: failed to read mt7530 register
[ 18.360696] mtk_soc_eth 15100000.ethernet: mdio: MDIO timeout
[ 18.367009] mt7530-mdio mdio-bus:1f: failed to read mt7530 register
[ 18.374606] mt7530-mdio mdio-bus:1f: reset timeout
[ 18.380775] mt7530-mdio: probe of mdio-bus:1f failed with error -110

From the information in https://forum.banana-pi.org/t/sfp-oem-sfp-2-5g-t-kernel-phy/15872/116 there appears to be an issue with some clocks that get disabled by the kernel.

Reported work arounds are to compile mtk-eth as built-in driver, or to stop the kernel from disabling clocks via the kernel parameter "clk_ignore_unused".

I used the kernel parameter work around and the mt7530 driver now loads:
[ 14.969089] mt7530-mdio mdio-bus:1f: configuring for fixed/2500base-x link mode
[ 14.972329] mt7530-mdio mdio-bus:1f: Link is Up - 2.5Gbps/Full - flow control rx/tx

I am not sure if this clock bug has been fixed in a more recent kernel release.