Re: Regression in v4.20 with net phy soft reset changes

[Heiner Kallweit]

On 09.01.2019 20:06, Tony Lindgren wrote:
> Hi all,
> 
> Commit 6e2d85ec0559 ("net: phy: Stop with excessive soft reset") caused
> a regression where suspend resume cycle fails to bring up Ethernet on at
> least cpsw on am437x-sk-evm.
> 
What kind of PHY and which PHY driver is used with this board?
I found one schematics of am437x where a KSZ9031RN PHY is used.
Is it the same on your board?

As described in the commit message of this commit you would have
the option to implement the soft_reset callback in the PHY driver.
Can you try to add .soft_reset = genphy_soft_reset to the
KSZ9031 driver config in drivers/net/phy/micrel.c and check whether
it fixes the issue?

> Keerthy noticed this may not happen on the first resume, but usually
> happens after few suspend resume cycles. The most working suspend resume
> cycles I've seen with the commit above is three.
> 
> Any ideas what might be going wrong?
> 
> Note that unrelated to the commit above, there may be other issues too
> as the cpsw phy LED seems to come on only after about five seconds with
> about total of 10 seconds before the Ethernet is up again.
> 
> Regards,
> 
> Tony
> 
Heiner