Bug 7770

Created attachment 10004 [details]
dmesg, lspci, ethtool, kernel configs

On Thu, 4 Jan 2007 08:49:49 -0800
bugme-daemon@bugzilla.kernel.org wrote:

> http://bugzilla.kernel.org/show_bug.cgi?id=7770
> 
>            Summary: Network connection randomly drops
>     Kernel Version: 2.6.19 onward
>             Status: NEW
>           Severity: normal
>              Owner: acme@conectiva.com.br
>          Submitter: prusnik@gmail.com
> 
> 
> Most recent kernel where this bug did *NOT* occur: 2.6.19-rc4
> Distribution: ubuntu 6.10, 64 bit
> Hardware Environment: ASUS M2N-E (MCP55), AMD X2 4200+
> Software Environment: normal linux distro with a custom kernel
> Problem Description:
> It started when I compiled the stable 2.6.19 kernel (first after rc4). The
> network connection to the router just dropped and I can find no reason why it is
> so. I have to revive the connection via /etc/init.d/networking restart command
> and the connection is there again. At first I was doing remote connection
> (tsclient in ubuntu) on another ubuntu dapper machine. The connection would
> randomly terminate. I assumed it was the program, but then I did a further test.
> I used mc (midnight commander) to copy some large files (a couple ubuntu iso-s)
>  to this machine (which acts as a file server) via NFS (and via router) and
> back. The connection would drop! The event is more frequent if I transfer the
> files from that computer than vice versa.
> I then rerun linux with 2.6.19-rc4 kernel and transfers were stable without a
> single connection drop. I then assumed it should be the newer forcedeth driver
> to blame but apparently it isn't. I put the 0.57 driver into the 2.6.20-rc3 and
> the problem persists. I even tried this patch from the bug #7684 but this didn't
> help either.
> 
> Steps to reproduce:
> Hopefully with this hardware I mentioned, plain ubuntu 6.10 64 bit installation
> with a kernel higher than 2.6.19-rc4. Config and other status files are in the
> attachment.
> 

It apparently was a configuration error. I compiled kernels from 2.6.19-rc5
onwards with the config of rc4, stripped of all obsoleted and deprecated items
in the network configuration (including network devices) and the copying tests
went through without a single connection drop.

Apologies for any inconveniences. Am attaching the 2.6.19 config if anyone has
dugg into this.

Created attachment 10038 [details]
the working config for 2.6.19

In case anyone will be reading this: it was the NAPI that was causing connection
drops. After I disabled it in the kernel config and recompiled the kernel it was
ok. 
The comment for NAPI say it's experimental so I guess it still needs a bit of
debugging.

Created attachment 11599 [details]
linux-2.6.20-gentoo-r8/.config

If needed, here is my kernel .config for linux-2.6.20-gentoo-r8

I always keep experimental features away from my kernel and same with NAPI for
forcedeth. But I enable NAPI for the Intel card where it is shown as
non-experimental.