[rt2x00-users] [bugzilla-daemon at bugzilla.kernel.org: [Bug 42828] rt2800pci unstable - chokes after too much I/O]

Andreas Hartmann andihartmann at 01019freenet.de
Sun Oct 21 20:02:20 AEDT 2012

Francisco Pina Martins wrote:
> Here is my update on this:
> I cannot boot with the patched kernel - I get a kernel panic at about 9
> secs during boot.

Stanislaws patch hangs the machine for me, too. See my other post.

> I have 2 more computers that connect to my routers frequently and without
> issue:
> One has an intel 4950 wireless card (currently using kernel 3.6.2, and
> never had any issues);
> The other one also has a ralink wireless card (not sure about the model
> though - i can check later if it is relevant),

It is relevant. Which kernel version? Which driver?

> but that one is running
> ubuntu 12.04, which has an older kernel so I wouldn't see the bug anyway.

Please don't think all users would use Ubuntu :-). Please add
the complete kernel version!

One more thing:
The problem usually only comes up if the connection is bad (e.g. high
distance or in common bad receiving conditions).
You wrote, that the other devices wouldn't show the behaviour you
described for your 2872 chipset with your AP. This doesn't prove anything.
Are they located at the same place or maybe at a place where the
receiving conditions are even worse?
Could you please test it with several bad receiving conditions using
netperf (about 30 minutes - see below) to get resilient behaviour.

> I have applied the patch using "patch -Np1 -l -i ap.patch".

Where did you apply the patch? Do you use compat-wireless?


BTW: Testing is much easier and more reliably using netperf. This tool
is very good to test the quality / throughput / behaviour of a connection!


Running netperf is easy. You have to install it on two machines. These
are the machines between the stream should be tested. In your case: the
machine before the AP and the machine behind the AP.
You start "netserver" on the machine behind the AP and the following
script on the machine before the AP:


dest="[the name or ip of the machine behind the AP]"

while true ; do
netperf -t TCP_MAERTS -H $dest
netperf -t TCP_STREAM -H $dest
netperf -t TCP_SENDFILE -H $dest

You can stop this script with CTRL-C

At the same time you may run xosview +n to get an actual view of the
network throughput. This enables you to see even short breaks e.g. The
Throughput as shown by xosview +n should be stable and the throughput
shown by netperf should be constantly at least 8MB/s (until 16 MB/s in
one direction) in both directions (MAERTS vs. STREM/SENDFILE) with
2.4GHz / 40MHz according netperf (not xosview - value of xosview will be
(much) higher).

kind regards,

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