network: Network auto-negotiation duplex fix for LAN8742 #4171
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On auto-negotiation using the external network phy LAN8742, the reference stm32f427 source code incorrectly uses the wrong PHY_SR (status register) addr of 0x10, leading to a false detection of the duplex mode, thus using half-duplex instead of duplex mode, resulting in retransmissions and overall lower throughput of data.
According to the LAN8742a datasheet, page 89, "4.2.22 PHY Special Control/Status Register" the addr is defined as 31 (0x1E), with duplex/half-duplex speed indicator given in bit 4..2.
This patch fixes the duplex mode for the ethernetif.c ... it might be necessary to patch the legacy HAL_ETH_Init as well within the lib/Drivers/STM32F4xx_HAL_Driver/Src/Legacy/stm32f4xx_hal_eth.c.
See further details here as well for reference.
Somewhat related to issue #3049 (not for wifi, but ethernet part)