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authorFeng Tang <feng.tang@intel.com>2016-06-24 15:26:05 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-07-27 09:55:47 -0700
commitfc70a4a5cb616bf390cee03390265045de5cf06a (patch)
tree043da02f60bb29ce569cba63d4a3a17d4ee8d68c /drivers
parentff790d971c10a4284c18ec4321b93246eb131e9f (diff)
downloadlwn-fc70a4a5cb616bf390cee03390265045de5cf06a.tar.gz
lwn-fc70a4a5cb616bf390cee03390265045de5cf06a.zip
net: alx: Work around the DMA RX overflow issue
[ Upstream commit 881d0327db37ad917a367c77aff1afa1ee41e0a9 ] Note: This is a verified backported patch for stable 4.4 kernel, and it could also be applied to 4.3/4.2/4.1/3.18/3.16 There is a problem with alx devices, that the network link will be lost in 1-5 minutes after the device is up. >From debugging without datasheet, we found the error always happen when the DMA RX address is set to 0x....fc0, which is very likely to be a HW/silicon problem. This patch will apply rx skb with 64 bytes longer space, and if the allocated skb has a 0x...fc0 address, it will use skb_resever(skb, 64) to advance the address, so that the RX overflow can be avoided. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=70761 Signed-off-by: Feng Tang <feng.tang@intel.com> Suggested-by: Eric Dumazet <edumazet@google.com> Tested-by: Ole Lukoie <olelukoie@mail.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/ethernet/atheros/alx/main.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/net/ethernet/atheros/alx/main.c b/drivers/net/ethernet/atheros/alx/main.c
index 3e1d7d29b4ec..758596021cf0 100644
--- a/drivers/net/ethernet/atheros/alx/main.c
+++ b/drivers/net/ethernet/atheros/alx/main.c
@@ -86,9 +86,14 @@ static int alx_refill_rx_ring(struct alx_priv *alx, gfp_t gfp)
while (!cur_buf->skb && next != rxq->read_idx) {
struct alx_rfd *rfd = &rxq->rfd[cur];
- skb = __netdev_alloc_skb(alx->dev, alx->rxbuf_size, gfp);
+ skb = __netdev_alloc_skb(alx->dev, alx->rxbuf_size + 64, gfp);
if (!skb)
break;
+
+ /* Workround for the HW RX DMA overflow issue */
+ if (((unsigned long)skb->data & 0xfff) == 0xfc0)
+ skb_reserve(skb, 64);
+
dma = dma_map_single(&alx->hw.pdev->dev,
skb->data, alx->rxbuf_size,
DMA_FROM_DEVICE);