From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:41966 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755512AbaCFBuf (ORCPT ); Wed, 5 Mar 2014 20:50:35 -0500 From: Laurent Pinchart To: Joe Perches Cc: Mauro Carvalho Chehab , Paul Bolle , Greg Kroah-Hartman , linux-media@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] [media] v4l: omap4iss: Add DEBUG compiler flag Date: Thu, 06 Mar 2014 02:52:03 +0100 Message-ID: <18589524.VtEDRg43uX@avalon> In-Reply-To: <1394069742.12070.39.camel@joe-AO722> References: <1391958577.25424.22.camel@x220> <3032500.9J1uSX3lel@avalon> <1394069742.12070.39.camel@joe-AO722> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Joe, On Wednesday 05 March 2014 17:35:42 Joe Perches wrote: > On Thu, 2014-03-06 at 02:27 +0100, Laurent Pinchart wrote: > > On Wednesday 05 March 2014 17:00:37 Joe Perches wrote: > > > On Thu, 2014-03-06 at 01:48 +0100, Laurent Pinchart wrote: > > > > Would you recommend to drop driver-specific Kconfig options related to > > > > debugging and use CONFIG_DYNAMIC_DEBUG instead ? > > > > > > For development, sure, if there's sufficient memory. > > > For embedded systems with limited memory, using dynamic_debug isn't > > > always possible or effective. > > > Also, there are sometimes reasons to have debugging messages always > > > enabled or emitted. > > > For those cases, either adding #define DEBUG or using printk(KERN_DEBUG > > > would be fine. > > > > My goal here is to offer an easy way for users to enable debugging without > > requiring changes to the source code. > > Dynamic debugging works, but various distributions don't > have it enabled. > > > The driver includes various dev_dbg() messages, I don't want to ask people > > reporting problems to turn them into printk() calls :-) Even adding > > #define DEBUG at the beginning of the source files is likely too error > > prone for users without much programming experience. > > I think your best bet is to add #define DEBUG to a common > header file like iss.h or omap4iss.h I've thought about that, but it would require iss.h to be included before all other headers. I've also thought about creating an iss-debug.h header to be included first just to #define DEBUG, but decided to go for handling the OMAP4 ISS debug option in the Makefile instead. If that's ugly and discouraged as reported by Mauro I can try to come up with something else. -- Regards, Laurent Pinchart