netdev - Re: cdc_ncm kernel log spam with trendnet 2.5G USB adapter

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Message-ID: <b8adbaa04c984cd49448e4f82b16393e3b8d7930.camel@suse.com>
Date:   Thu, 26 Nov 2020 13:05:31 +0100
From:   Oliver Neukum <oneukum@...e.com>
To:     Roland Dreier <roland@...nel.org>, netdev@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: Re: cdc_ncm kernel log spam with trendnet 2.5G USB adapter

Am Montag, den 16.11.2020, 09:23 -0800 schrieb Roland Dreier:
> Hi, I recently got a 2.5G USB adapter, and although it works fine, the
> driver continually spams the kernel log with messages like
> 
> [127662.025647] cdc_ncm 4-1:2.0 enx3c8cf8f942e0: network connection: connected
> [127662.057680] cdc_ncm 4-1:2.0 enx3c8cf8f942e0: 2500 mbit/s downlink
> 2500 mbit/s uplink
> [127662.089794] cdc_ncm 4-1:2.0 enx3c8cf8f942e0: network connection: connected
> [127662.121831] cdc_ncm 4-1:2.0 enx3c8cf8f942e0: 2500 mbit/s downlink
> 2500 mbit/s uplink
> [127662.153858] cdc_ncm 4-1:2.0 enx3c8cf8f942e0: network connection: connected
> ...
> 
> Looking at the code in cdc_ncm.c it seems the device is just sending
> USB_CDC_NOTIFY_NETWORK_CONNECTION and USB_CDC_NOTIFY_SPEED_CHANGE urbs
> over and over, and the driver logs every single one.
> 
> Should we add code to the driver to keep track of what the last event
> was and only log if the state has really change?

Hi,

in theory I suppose we could do that, but it would be kind of stupid.
Events like these should be reported to higher layers and not logged at
all.

	Regards
		Oliver