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

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Date:   Mon, 7 May 2018 21:11:21 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     David Miller <davem@...emloft.net>,
        Realtek linux nic maintainers <nic_swsd@...ltek.com>
Cc:     Slava Kardakov <ojab@...b.ru>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net] r8169: fix powering up RTL8168h

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@...b.ru>
Tested-by: Slava Kardakov <ojab@...b.ru>
Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
This patch will not apply to net-next as it conflicts with other
changes which have been done in the meantime. So I'll send a
separate patch for net-next.
---
 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 604ae783..c7aac1fc 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -4981,6 +4981,9 @@ static void rtl_pll_power_down(struct rtl8169_private *tp)
 static void rtl_pll_power_up(struct rtl8169_private *tp)
 {
 	rtl_generic_op(tp, tp->pll_power_ops.up);
+
+	/* give MAC/PHY some time to resume */
+	msleep(20);
 }

 static void rtl_init_pll_power_ops(struct rtl8169_private *tp)
-- 
2.17.0