target/linux/mediatek/patches-4.4/0088-net-next-mediatek-fix-threshold-value.patch

   1 From 34ea0f209e0759158e363039852a04b1facc3acd Mon Sep 17 00:00:00 2001
   2 From: John Crispin <john@phrozen.org>
   3 Date: Tue, 3 May 2016 02:55:27 +0200
   4 Subject: [PATCH 088/102] net-next: mediatek: fix threshold value
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   8
   9 The logic to calculate the threshold value for stopping the TX queue is
  10 bad. Currently it will always use 1/2 of the rings size, which is way too
  11 much. Set the threshold to MAX_SKB_FRAGS. This makes sure that the queue
  12 is stopped when there is not enough room to accept an additional segment.
  13
  14 Signed-off-by: John Crispin <john@phrozen.org>
  15 ---
  16  drivers/net/ethernet/mediatek/mtk_eth_soc.c |    3 +--
  17  1 file changed, 1 insertion(+), 2 deletions(-)
  18
  19 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  20 +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  21 @@ -1043,8 +1043,7 @@ static int mtk_tx_alloc(struct mtk_eth *
  22         atomic_set(&ring->free_count, MTK_DMA_SIZE - 2);
  23         ring->next_free = &ring->dma[0];
  24         ring->last_free = &ring->dma[MTK_DMA_SIZE - 2];
  25 -       ring->thresh = max((unsigned long)MTK_DMA_SIZE >> 2,
  26 -                             MAX_SKB_FRAGS);
  27 +       ring->thresh = MAX_SKB_FRAGS;
  28
  29         /* make sure that all changes to the dma ring are flushed before we
  30          * continue