[PATCH net-next] r8169: fix powering up RTL8168h

[Heiner Kallweit <hkallweit1@gmail.com>]

Since commit a92a08499b1f "r8169: improve runtime pm in general and
suspend unused ports" interfaces w/o link are runtime-suspended after
10s. On systems where drivers take longer to load this can lead to the
situation that the interface is runtime-suspended already when it's
initially brought up.
This shouldn't be a problem because rtl_open() resumes MAC/PHY.
However with at least one chip version the interface doesn't properly
come up, as reported here:
https://bugzilla.kernel.org/show_bug.cgi?id=199549

The vendor driver uses a delay to give certain chip versions some
time to resume before starting the PHY configuration. So let's do
the same. I don't know which chip versions may be affected,
therefore apply this delay always.

This patch was reported to fix the issue for RTL8168h.
I was able to reproduce the issue on an Asus H310I-Plus which also
uses a RTL8168h. Also in my case the patch fixed the issue.

Reported-by: Slava Kardakov <ojab@ojab.ru>
Tested-by: Slava Kardakov <ojab@ojab.ru>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/net/ethernet/realtek/r8169.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 6d99b141..a60207a5 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -4662,6 +4662,9 @@ static void r8168_phy_power_up(struct rtl8169_private *tp)
 		break;
 	}
 	rtl_writephy(tp, MII_BMCR, BMCR_ANENABLE);
+
+	/* give PHY some time to resume */
+	msleep(20);
 }
 
 static void r8168_phy_power_down(struct rtl8169_private *tp)
-- 
2.17.0