On 03/05/16 05:55, John Stultz wrote:
In testing with HiKey, we found that since commit 3f30b158eba5c60
(asix: On RX avoid creating bad Ethernet frames), we're seeing lots of
noise during network transfers:
[ 239.027993] asix 1-1.1:1.0 eth0: asix_rx_fixup() Data Header
synchronisation was lost, remaining 988
[ 239.037310] asix 1-1.1:1.0 eth0: asix_rx_fixup() Bad Header Length
0x54ebb5ec, offset 4
[ 239.045519] asix 1-1.1:1.0 eth0: asix_rx_fixup() Bad Header Length
0xcdffe7a2, offset 4
[ 239.275044] asix 1-1.1:1.0 eth0: asix_rx_fixup() Data Header
synchronisation was lost, remaining 988
[ 239.284355] asix 1-1.1:1.0 eth0: asix_rx_fixup() Bad Header Length
0x1d36f59d, offset 4
[ 239.292541] asix 1-1.1:1.0 eth0: asix_rx_fixup() Bad Header Length
0xaef3c1e9, offset 4
[ 239.518996] asix 1-1.1:1.0 eth0: asix_rx_fixup() Data Header
synchronisation was lost, remaining 988
[ 239.528300] asix 1-1.1:1.0 eth0: asix_rx_fixup() Bad Header Length
0x2881912, offset 4
[ 239.536413] asix 1-1.1:1.0 eth0: asix_rx_fixup() Bad Header Length
0x5638f7e2, offset 4
And network throughput ends up being pretty bursty and slow with a
overall throughput of at best ~30kB/s.
Looking through the commits since the v4.1 kernel where we didn't see
this, I narrowed the regression down, and reverting the following two
commits seems to avoid the problem:
6a570814cd430fa5ef4f278e8046dcf12ee63f13 asix: Continue processing URB
if no RX netdev buffer
3f30b158eba5c604b6e0870027eef5d19fc9271d asix: On RX avoid creating
bad Ethernet frames
With these reverted, we don't see all the error messages, and we see
better ~1.1MB/s throughput (I've got a mouse plugged in, so I think
the usb host is only running at "full-speed" mode here).
This worries me some, as the patches seem to describe trying to fix
the issue they seem to cause, so I suspect a revert isn't the correct
solution, but am not sure why we're having such trouble and the patch
authors did not. I'd be happy to do further testing of patches if
folks have any ideas.
Originally Reported-by: Yongqin Liu <yongqin.liu@xxxxxxxxxx>
thanks
-john
Hi John,
Some ASIX chipsets span the Ethernet frame over consecutive URBs which
requires successful transfer of 2 URBs.
This means states of a previous URB influences the processing of the
next URB including a dropped URB (causes a discontinuity in the data
stream). In other words synchronisation of the in-band 32-bit header
word needs to be tracked between URBs. Some ASIX chipsets allow the
in-band 32-bit header word to be no longer fixed to the start of the URB
buffer so it moves to any position within the URB buffer.
I understand your point of suggesting it is a "regression" for your
device but the driver was broken for DUB-E100 C1 (small black USB
device). So you cannot revert the commits as this would break DUB-E100
C1 (small black USB device).
6a570814cd430fa5ef4f278e8046dcf12ee63f13 asix: Continue processing URB
if no RX netdev buffer
This commit is necessary because it avoids a crash when netdev buffer
failed to be allocated for the 1st URB and the 2nd URB containing a
spanned Ethernet frame is processed. The crash happens because the 2nd
URB assumed that the netdev buffer had been allocated.
3f30b158eba5c604b6e0870027eef5d19fc9271d asix: On RX avoid creating
bad Ethernet frames
This commit is necessary to avoid sending bad Ethernet frames into the
IP stack during loss of synchronisation and to dropping good Ethernet
frames. This commit improves the synchronisation recovery mechanism of
the in-band 32-bit header word.
The ASIX USB to Ethernet devices these commits were tested on where
DUB-E100 C1 (small black USB device). Embedded ARM based systems were
used where memory resources can run out.
It could be that for your USB to Ethernet device that the wrong
configuration settings have been used. In other words the ASIX driver is
flexible to support various variants of the ASIX chipsets. For example,
does your device support Ethernet frames spanning multiple URBs
(multiple USB transfers) ?
So I doubt my commits are "broken" because we don't see your failures
(not tested your device). It is more likely that your ASIX device needs
to be properly identified and configured to be compatible with the ASIX
driver. At least, I suggest that is the best place to start your
investigation.
Of course, your ASIX chipset might have a different behaviour for how
the in-band 32-bit header word operates so perhaps special treatment is
needed for your chipset ?
Please send to the mailing list the output of lsusb for your device so
that people can know the USB product ID and vendor ID for your device.
This is allows people to assist with the investigation. Do you have any
links to websites that sell your device ?
Are you using UDP or TCP connections ?
Regards,
Dean
--
Dean Jenkins
Embedded Software Engineer
Linux Transportation Solutions
Mentor Embedded Software Division
Mentor Graphics (UK) Ltd.
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