I got it. Thanks.

-----Original Message-----
From: David Miller [mailto:davem@davemloft.net] 
Sent: Wednesday, October 19, 2011 3:50 PM
To: Ren, Cloud
Cc: Rodriguez, Luis; netdev@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [patch net-next]alx: Atheros AR8131/AR8151/AR8152/AR8161 Ethernet driver

From: "Ren, Cloud" <redacted>
Date: Wed, 19 Oct 2011 07:44:02 +0000

Ok. What logging interfaces can I use? Are they dev_err, dev_info and 
dev_warn ? thanks

netif_*(), they check netif_msg_*() to see if the particular kind of logging message is enabled or not, and this can be set dynamically if you code your driver to properly set netdev->msg_enable.

Use other drivers as examples.