Re: [PATCH V3 net 2/2] net: phy: at803x: add disable hibernation mode support

Andrew Lunn
2022-08-18T19:29:24Z

On Thu, Aug 18, 2022 at 11:00:54AM +0800, wei.fang@nxp.com wrote:
> From: Wei Fang <wei.fang@nxp.com>
>
> When the cable is unplugged, the Atheros AR803x PHYs will enter
> hibernation mode after about 10 seconds if the hibernation mode
> is enabled and will not provide any clock to the MAC. But for
> some MACs, this feature might cause unexpected issues due to the
> logic of MACs.
> Taking SYNP MAC (stmmac) as an example, if the cable is unplugged
> and the "eth0" interface is down, the AR803x PHY will enter
> hibernation mode. Then perform the "ifconfig eth0 up" operation,
> the stmmac can't be able to complete the software reset operation
> and fail to init it's own DMA. Therefore, the "eth0" interface is
> failed to ifconfig up. Why does it cause this issue? The truth is
> that the software reset operation of the stmmac is designed to
> depend on the RX_CLK of PHY.
> So, this patch offers an option for the user to determine whether
> to disable the hibernation mode of AR803x PHYs.
>
> Signed-off-by: Wei Fang <wei.fang@nxp.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

Andrew