[ 182/218] r8169: RxConfig hack for the 8168evl.

From: Greg Kroah-Hartman
Date: Fri Sep 28 2012 - 16:32:30 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Francois Romieu <romieu@xxxxxxxxxxxxx>

commit eb2dc35d99028b698cdedba4f5522bc43e576bd2 upstream.

The 8168evl (RTL_GIGA_MAC_VER_34) based Gigabyte GA-990FXA motherboards
are very prone to NETDEV watchdog problems without this change. See
https://bugzilla.kernel.org/show_bug.cgi?id=42899 for instance.

I don't know why it *works*. It's depressingly effective though.

For the record:
- the problem may go along IOMMU (AMD-Vi) errors but it really looks
like a red herring.
- the patch sets the RX_MULTI_EN bit. If the 8168c doc is any guide,
the chipset now fetches several Rx descriptors at a time.
- long ago the driver ignored the RX_MULTI_EN bit.
e542a2269f232d61270ceddd42b73a4348dee2bb changed the RxConfig
settings. Whatever the problem it's now labeled a regression.
- Realtek's own driver can identify two different 8168evl devices
(CFG_METHOD_16 and CFG_METHOD_17) where the r8169 driver only
sees one. It sucks.

Signed-off-by: Francois Romieu <romieu@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>

---
drivers/net/ethernet/realtek/r8169.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -3737,6 +3737,7 @@ static void rtl_init_rxcfg(struct rtl816
case RTL_GIGA_MAC_VER_22:
case RTL_GIGA_MAC_VER_23:
case RTL_GIGA_MAC_VER_24:
+ case RTL_GIGA_MAC_VER_34:
RTL_W32(RxConfig, RX128_INT_EN | RX_MULTI_EN | RX_DMA_BURST);
break;
default:


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