The PHY probing of the macb driver appears to be rather unreliable. Most of the time it doesn't work the first time, I have to reload the module several times to let it succeed.
[ 40.530000] macb: GEM doesn't support hardware ptp. [ 40.530000] libphy: MACB_mii_bus: probed [ 41.450000] macb 10090000.ethernet (unnamed net_device) (uninitialized): Could not attach to PHY [ 41.510000] macb: probe of 10090000.ethernet failed with error -110 [ 1354.400000] macb: GEM doesn't support hardware ptp. [ 1354.410000] libphy: MACB_mii_bus: probed [ 1355.260000] macb 10090000.ethernet (unnamed net_device) (uninitialized): Could not attach to PHY [ 1355.300000] macb: probe of 10090000.ethernet failed with error -110 [ 1358.100000] macb: GEM doesn't support hardware ptp. [ 1358.110000] libphy: MACB_mii_bus: probed [ 1358.310000] Microsemi VSC8541 SyncE 10090000.ethernet-ffffffff:00: attached PHY driver [Microsemi VSC8541 SyncE] (mii_bus:phy_addr=10090000.ethernet-ffffffff:00, irq=POLL) [ 1358.320000] macb 10090000.ethernet eth0: Cadence GEM rev 0x10070109 at 0x10090000 irq 12 (70:b3:d5:92:f1:07) This is 4.20-rc4 on a HiFive-U. Andreas. -- Andreas Schwab, SUSE Labs, sch...@suse.de GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 "And now for something completely different."