Hello:
This patch was applied to netdev/net.git (main) by Jakub Kicinski kuba@kernel.org:
On Mon, 29 Jan 2024 23:49:48 +0100 you wrote:
Not all mv88e6xxx device support C45 read/write operations. Those which do not return -EOPNOTSUPP. However, when phylib scans the bus, it considers this fatal, and the probe of the MDIO bus fails, which in term causes the mv88e6xxx probe as a whole to fail.
When there is no device on the bus for a given address, the pull up resistor on the data line results in the read returning 0xffff. The phylib core code understands this when scanning for devices on the bus. C45 allows multiple devices to be supported at one address, so phylib will perform a few reads at each address, so although thought not the most efficient solution, it is a way to avoid fatal errors. Make use of this as a minimal fix for stable to fix the probing problems.
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Here is the summary with links: - [net,v2] net: dsa: mv88e6xxx: Fix failed probe due to unsupported C45 reads https://git.kernel.org/netdev/net/c/585b40e25dc9
You are awesome, thank you!