Re: [PATCH] e1000e: Power cycle phy on PM resume

Andrew Lunn
2020-09-23T12:18:01Z

On Wed, Sep 23, 2020 at 03:47:51PM +0800, Kai-Heng Feng wrote:
> We are seeing the following error after S3 resume:
> [ 704.746874] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
> [ 704.844232] e1000e 0000:00:1f.6 eno1: MDI Write did not complete
> [ 704.902817] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
> [ 704.903075] e1000e 0000:00:1f.6 eno1: reading PHY page 769 (or 0x6020 shifted) reg 0x17
> [ 704.903281] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
> [ 704.903486] e1000e 0000:00:1f.6 eno1: writing PHY page 769 (or 0x6020 shifted) reg 0x17
> [ 704.943155] e1000e 0000:00:1f.6 eno1: MDI Error
> ...
> [ 705.108161] e1000e 0000:00:1f.6 eno1: Hardware Error
>
> Since we don't know what platform firmware may do to the phy, so let's
> power cycle the phy upon system resume to resolve the issue.
>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
> drivers/net/ethernet/intel/e1000e/netdev.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index 664e8ccc88d2..c2a87a408102 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -6968,6 +6968,8 @@ static __maybe_unused int e1000e_pm_resume(struct device *dev)
> !e1000e_check_me(hw->adapter->pdev->device))
> e1000e_s0ix_exit_flow(adapter);
>
> + e1000_power_down_phy(adapter);
> +

static void e1000_power_down_phy(struct e1000_adapter *adapter)
{
struct e1000_hw *hw = &adapter->hw;

/* Power down the PHY so no link is implied when interface is down *
* The PHY cannot be powered down if any of the following is true *
* (a) WoL is enabled
* (b) AMT is active
* (c) SoL/IDER session is active
*/
if (!adapter->wol && hw->mac_type >= e1000_82540 &&
hw->media_type == e1000_media_type_copper) {

Could it be coming out of S3 because it just received a WoL?

It seems unlikely that it is the MII_CR_POWER_DOWN which is helping,
since that is an MDIO write itself. Do you actually know how this call
to e1000_power_down_phy() fixes the issues?

Andrew