Date: Thu, 7 Dec 2006 18:26:56 +0100
From: Adrian Bunk <bunk@stusta.de>
To: Michael Krufky <mkrufky@linuxtv.org>
Cc: mchehab@infradead.org, v4l-dvb-maintainer@linuxtv.org,
       linux-kernel@vger.kernel.org
Subject: Re: [v4l-dvb-maintainer] [2.6 patch] cx88/saa7134: remove unused -DHAVE_VIDEO_BUF_DVB
Message-ID: <20061207172656.GL8963@stusta.de>
References: <20061207150028.GJ8963@stusta.de> <457834E1.1090406@linuxtv.org> <20061207164245.GK8963@stusta.de> <45784BD7.7010605@linuxtv.org>
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On Thu, Dec 07, 2006 at 12:13:59PM -0500, Michael Krufky wrote:
> Adrian Bunk wrote:
> > On Thu, Dec 07, 2006 at 10:36:01AM -0500, Michael Krufky wrote:
> >> Adrian Bunk wrote:
> >>> This patch removes the unused HAVE_VIDEO_BUF_DVB define.
> 
> [snip]
> 
> >> ...We need this in order to allow compilation of the cx88 / saa7134 modules
> >> without DVB support. (analog only)
> >  
> > Ah, you added them in v4l-dvb last year.
> 
> You are correct:  Tue Oct 11 20:11:34 2005 +0000 (14 months ago)
> 
> http://linuxtv.org/hg/v4l-dvb?cmd=changeset;node=56cf49b544f0
> 
> > But they are neither in Linus' tree nor in the v4l-dvb git tree that is 
> > in the latest -mm.
> 
> hmm... looks like some changesets never made it over to git from our hg tree.
> 
> > Compilation of cx88 and saa7134 without DVB works fine in these trees, 
> > so what's the story behind this?
> 
> It's a bug -- looks like CONFIG_VIDEO_BUF_DVB is being enabled, regardless
> of whether or not it is selected -- otherwise we'd get other compiler errors,
> because both cx88 and saa7134 have dependencies on video-buf-dvb.


No, the configuration

  CONFIG_VIDEO_SAA7134=y
  CONFIG_VIDEO_SAA7134_DVB=n
  CONFIG_VIDEO_BUF_DVB=n

builds fine in 2.6.19.


Only the saa7134-dvb and cx88-dvb modules require video-buf-dvb, and the 
config options for them select VIDEO_BUF_DVB.


> VIDEO_BUF_DVB is being build without it's dependency, DVB_CORE -- that is
> the only reason why the build is still working, but it sounds unstable to me.


No, that's already handled correctly by both VIDEO_CX88_DVB and 
VIDEO_SAA7134_DVB depending on DVB_CORE.


> CONFIG_VIDEO_BUF_DVB is set inside drivers/media/Kconfig, with zero
> dependencies... In fact, VIDEO_BUF_DVB "depends on DVB_CORE" , but
> this is not being reflected in Kconfig.
> 
> Hmm... looks like a bit of a mess.
> 
> The story is much clearer now... Looks like we should in fact apply your
> patch, Adrian, but we will also have to make the following additional
> changes:
> 
> - add "depends on DVB_CORE" to the Kconfig entry for VIDEO_BUF_DVB


That would be a noop since VIDEO_BUF_DVB is a not user visible option 
that gets select'ed.


> - convert the #ifdef tests in the hg repository for HAVE_VIDEO_BUF_DVB
> 	to look for the CONFIG_VIDEO_BUF_DVB instead
> - generate a patch against Linus' tree that add's these #ifdefs to the
> 	cx88 and saa7134 drivers.


There is no problem these #ifdef's would solve in Linus' tree...


> If you dont mind, I'd like to take care of this stuff myself.  I will prepare
> these patches tomorrow, and I'll have them applied to both our v4l-dvb.hg
> repository on linuxtv.org, and I'll also ask Mauro to merge them into his git
> tree before his next pull request to Linus.
> 
> Thanks, Adrian, for pointing out this inconsistency.
> 
> Cheers,
> 
> Michael Krufky


cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

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