This is a note to let you know that I've just added the patch titled
net: alx: Work around the DMA RX overflow issue
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-alx-work-around-the-dma-rx-overflow-issue.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Jul 6 17:30:58 PDT 2016
From: Feng Tang <feng.tang@xxxxxxxxx>
Date: Fri, 24 Jun 2016 15:26:05 +0800
Subject: net: alx: Work around the DMA RX overflow issue
Status: RO
Content-Length: 1764
Lines: 47
From: Feng Tang <feng.tang@xxxxxxxxx>
[ 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@xxxxxxxxx>
Suggested-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Tested-by: Ole Lukoie <olelukoie@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/atheros/alx/main.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- 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
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);
Patches currently in stable-queue which might be from feng.tang@xxxxxxxxx are
queue-3.14/net-alx-work-around-the-dma-rx-overflow-issue.patch
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