From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752842Ab0CRWUc (ORCPT ); Thu, 18 Mar 2010 18:20:32 -0400 Received: from kroah.org ([198.145.64.141]:37855 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751450Ab0CRWUa (ORCPT ); Thu, 18 Mar 2010 18:20:30 -0400 Date: Thu, 18 Mar 2010 15:19:58 -0700 From: Greg KH To: Sarah Sharp Cc: Alex Chiang , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/2] small xhci cleanups Message-ID: <20100318221958.GB3299@kroah.com> References: <20100316204845.GJ8278@ldl.fc.hp.com> <20100309184723.GA31374@kroah.com> <20100316212445.GA15729@xanatos> <20100316214014.GA8839@kroah.com> <20100318213308.GA5461@xanatos> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100318213308.GA5461@xanatos> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 18, 2010 at 02:33:08PM -0700, Sarah Sharp wrote: > On Tue, Mar 16, 2010 at 02:40:14PM -0700, Greg KH wrote: > > On Tue, Mar 16, 2010 at 02:24:45PM -0700, Sarah Sharp wrote: > > > Ok, I didn't see Greg's email about dynamic debugging. I guess you > > > shouldn't refresh the second patch. I'm not sure how I would go about > > > converting the xHCI driver to dynamic debugging, as I haven't looked > > > into it. Is there any documentation/simple examples? > > > > Yes, just use 'dev_dbg' and you are finished. > > > > Or pr_debug if you want to use different logging levels with your > > macros. > > > > > Greg, does the less-verbose patch with log levels still make sense if > > > the driver got converted over to dynamic debugging? > > > > I don't know what people really want to see. In 6 months you will > > probably only care about "debugging on or off" as the majority of the > > messages only help you out when developing the driver, right? > > "On" or "off" doesn't really help when you're trying to debug different > parts of the driver. If you're trying to debug a command, messages > about wrapping rings or enqueueing transfers doesn't really matter. Like Roland, I recommend the tracing interface for this. > I think the end user doesn't want to see anything from the driver unless > something serious has gone wrong. But those cases use xhci_warn(), > which translates down to dev_warn(), instead of xhci_dbg(). Yes, that's fine. But you need/want something for when a user reports a problem, and they can't rebuild their kernel. > > So maybe par down some of the messages, or just live with seeing them > > all, it will be easier in the end. > > Yes, I did par down the duplicate/redundant messages, but I still want > to see very detailed messages when I think there's a hardware problem. > > What if I removed the debug config option for xHCI, allowed people to > use dynamic debugging to enable debugging for specific xHCI files, but > also allowed them to set the log level through a debugfs file? That way > people could still control the variety of messages that they see, but > they can also change the level of debugging dynamically. Sure, that might work, but I'd recommend tracing for the most part, that's what it is there for :) thanks, greg k-h