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author | Frank Li <Frank.Li@freescale.com> | 2013-07-25 06:05:53 (GMT) |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2013-07-28 03:14:48 (GMT) |
commit | 031916568a1aa2ef1809f86d26f0bcfa215ff5c0 (patch) | |
tree | cd6081f93a38a1eb924896ed77b53188e405bbe9 /net/netlink/genetlink.c | |
parent | c2534384233647a8702eca291199b94ffedc12d3 (diff) | |
download | linux-031916568a1aa2ef1809f86d26f0bcfa215ff5c0.tar.xz |
net: fec: workaround stop tx during errata ERR006358
If the ready bit in the transmit buffer descriptor (TxBD[R])
is previously detected as not set during a prior frame transmission,
then the ENET_TDAR[TDAR] bit is cleared at a later time, even if
additional TxBDs were added to the ring and the ENET_TDAR[TDAR]
bit is set. This results in frames not being transmitted until
there is a 0-to-1 transition on ENET_TDAR[TDAR].
Workarounds:
code can use the transmit frame interrupt flag (ENET_EIR[TXF])
as a method to detect whether the ENET has completed transmission
and the ENET_TDAR[TDAR] has been cleared. If ENET_TDAR[TDAR] is
detected as cleared when packets are queued and waiting for transmit,
then a write to the TDAR bit will restart TxBD processing.
This case main happen when loading is light. A ethernet package may
not send out utile next package put into tx queue.
How to test:
while [ true ]
do
ping <IP> -s 10000 -w 4
ping <IP> -s 6000 -w 2
ping <IP> -s 4000 -w 2
ping <IP> -s 10000 -w 2
done
You will see below result in overnight test.
6008 bytes from 10.192.242.116: seq=1 ttl=128 time=0.722 ms
4008 bytes from 10.192.242.116: seq=0 ttl=128 time=1001.008 ms
4008 bytes from 10.192.242.116: seq=1 ttl=128 time=1.010 ms
10008 bytes from 10.192.242.116: seq=0 ttl=128 time=0.896 ms
After apply this patch, >1000ms delay disappear.
Signed-off-by: Frank Li <Frank.Li@freescale.com>
Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink/genetlink.c')
0 files changed, 0 insertions, 0 deletions