openwrtv3/target/linux/mediatek/patches-4.4/0077-net-mediatek-do-not-set-the-QID-field-in-the-TX-DMA-.patch

From 2675e2a40d78c55fc2d578ec71cc990170cacc42 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Thu, 7 Apr 2016 17:36:23 +0200
Subject: [PATCH 77/91] net: mediatek: do not set the QID field in the TX DMA
 descriptors

The QID field gets set to the mac id. This made the DMA linked list queue
the traffic of each MAC on a different internal queue. However during long
term testing we found that this will cause traffic stalls as the multi
queue setup requires a more complete initialisation which is not part of
the upstream driver yet.

This patch removes the code setting the QID field, resulting in all
traffic ending up in queue 0 which works without any special setup.

Signed-off-by: John Crispin <blogic@openwrt.org>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -603,8 +603,7 @@ static int mtk_tx_map(struct sk_buff *sk
 			WRITE_ONCE(txd->txd1, mapped_addr);
 			WRITE_ONCE(txd->txd3, (TX_DMA_SWC |
 					       TX_DMA_PLEN0(frag_map_size) |
-					       last_frag * TX_DMA_LS0) |
-					       mac->id);
+					       last_frag * TX_DMA_LS0));
 			WRITE_ONCE(txd->txd4, 0);
 
 			tx_buf->skb = (struct sk_buff *)MTK_DMA_DUMMY_DESC;