Re: [Intel-wired-lan] [PATCH net] ixgbe: set X550 MDIO speed before talking to PHY
From: Paul Menzel <hidden>
Date: 2021-10-29 06:47:49
Also in:
intel-wired-lan
Dear Cyril, On 29.10.21 03:03, Cyril Novikov wrote:
The MDIO bus speed must be initialized before talking to the PHY the first time in order to avoid talking to it using a speed that the PHY doesn't support. This fixes HW initialization error -17 (IXGBE_ERR_PHY_ADDR_INVALID) on Denverton CPUs (a.k.a. the Atom C3000 family) on ports with a 10Gb network plugged in. On those devices, HLREG0[MDCSPD] resets to 1, which combined with the 10Gb network results in a 24MHz MDIO speed, which is apparently too fast for the connected PHY. PHY register reads over MDIO bus return garbage, leading to initialization failure.
Maybe add a Fixes tag?
Signed-off-by: Cyril Novikov <redacted> --- drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c | 3 +++ 1 file changed, 3 insertions(+) Reproduced with Linux kernel 4.19 and 5.15-rc7. Can be reproduced using the following setup: * Use an Atom C3000 family system with at least one X550 LAN on the SoC * Disable PXE or other BIOS network initialization if possible (the interface must not be initialized before Linux boots) * Connect a live 10Gb Ethernet cable to an X550 port * Power cycle (not reset, doesn't always work) the system and boot Linux * Observe: ixgbe interfaces w/ 10GbE cables plugged in fail with error -17
Why not add that to the commit message?
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c index 9724ffb16518..e4b50c7781ff 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c@@ -3405,6 +3405,9 @@ static s32 ixgbe_reset_hw_X550em(struct ixgbe_hw *hw) /* flush pending Tx transactions */ ixgbe_clear_tx_pending(hw); + /* set MDIO speed before talking to the PHY in case it's the 1st time */ + ixgbe_set_mdio_speed(hw); + /* PHY ops must be identified and initialized prior to reset */ status = hw->phy.ops.init(hw); if (status == IXGBE_ERR_SFP_NOT_SUPPORTED ||
Is `ixgbe_set_mdio_speed(hw)` at the end of the function then still needed? Kind regards, Paul