[Cerowrt-devel] Wireless failures 3.10.17-3

Dave Taht dave.taht at gmail.com
Wed Dec 11 13:41:42 EST 2013

I have the regrettable problem of mostly testing the 5ghz channel due
to interference issues on the 2ghz band.

What I am seeing in the last several releases of the 3.8.x and 3.10
series is after tons of traffic and multiple days of uptime a DMA tx
error which you can see via the logread or dmesg tool, and once it
happens, at least sometimes, that radio can "go away" and not be
resettable. "cannot stop tx dma" is the error. I have seen this error
many, many times in cerowrt releases for the last 2 years, but this
time it seems more severe than usual.

There was also a bug in dnsmasq or somewhere in the lower level of the
stack where it stops responding to multicast dhcp packets.

The upcoming 3.10.23-1 development release has a refresh of mac80211,
and a bug fix related to multicast, so I have some hope for it.

It has also the latest dnsmasq 2.68 (which fixes a bug in cname
handling in particular), and also pie v3 but I am (as usual) not in a
position to test it right now.

It is my hope that now that the bug happens a lot we can track it
down. Or, that it's fixed. :)

I just put that release up at:


It does not have the updated aqm-scripts code and gui (sorry
sebastian), nor the pie v4 drop that just got rejected for kernel
mainline. I'll try to do a respin this weekend with those, and poke
harder at the dma tx issue after I get back in the lab. Thoughts
towards being able to isolate the cause and minimize the effect are
welcomed - it's one of the biggest barriers to declaring a stable
release at this point!

On Wed, Dec 11, 2013 at 8:58 AM, Stephen Hemminger
<stephen at networkplumber.org> wrote:
> Has anyone seen wireless failing after several days with 3.10.17-3?
> The symptoms are devices fall off the net several days (or a week) after
> router has been running. I saw the bg AP go away, but the 5 Ghz AP still
> working. Wired attachment works.
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Dave Täht

Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html

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