Re: [PATCH] phy: added a PHY_BUSY state into phy_state_machine

[Andrew Lunn <andrew@lunn.ch>]

On Sun, Jul 07, 2019 at 06:32:12PM -0400, kwangdo.yi wrote:
> When mdio driver polling the phy state in the phy_state_machine,
> sometimes it results in -ETIMEDOUT and link is down. But the phy
> is still alive and just didn't meet the polling deadline. 
> Closing the phy link in this case seems too radical. Failing to 
> meet the deadline happens very rarely. When stress test runs for 
> tens of hours with multiple target boards (Xilinx Zynq7000 with
> marvell 88E1512 PHY, Xilinx custom emac IP), it happens. This 
> patch gives another chance to the phy_state_machine when polling 
> timeout happens. Only two consecutive failing the deadline is 
> treated as the real phy halt and close the connection.

Hi Kwangdo

I agree with Florian here. This does not seem like a PHY problem. It
is an MDIO bus problem. ETIMEDOUT is only returned from
xemaclite_mdio_wait().

What value are using for HZ? If you have 1000, jiffies + 2 could well
be too short.

   Andrew