linux-kernel - Re: [GIT PULL for v3.5-rc1] media updates for v3.5

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Message-ID: <4FBFACCA.1060308@iki.fi>
Date:	Fri, 25 May 2012 19:01:14 +0300
From:	Anssi Hannula <anssi.hannula@....fi>
To:	Mauro Carvalho Chehab <mchehab@...hat.com>
CC:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Media Mailing List <linux-media@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Guennadi Liakhovetski <g.liakhovetski@....de>,
	Thomas Backlund <tmb@...eia.org>
Subject: Re: [GIT PULL for v3.5-rc1] media updates for v3.5

25.05.2012 18:21, Mauro Carvalho Chehab kirjoitti:
> Em 25-05-2012 11:49, Anssi Hannula escreveu:
>> 25.05.2012 15:12, Mauro Carvalho Chehab kirjoitti:
>>> Em 24-05-2012 19:40, Linus Torvalds escreveu:
>>>> On Thu, May 24, 2012 at 3:33 PM, Mauro Carvalho Chehab
>>>> <mchehab@...hat.com> wrote:
>>>>>
>>>>> The Kconfig default for DVB_FE_CUSTOMISE is 'n'. So, if no DVB bridge is selected,
>>>>> nothing will be compiled.
>>>>
>>>> Sadly, it looks like the default for distro kernels is 'y'.
>>>
>>> I'll change the default on Fedora (f16/f17/rawhide).
>>>
>>>> Which means that if you start with a distro kernel config, and then
>>>> try to cut it down to match your system, you end up screwed in the
>>>> future - all the new hardware will default to on.
>>>>
>>>> At least that's how I noticed it. Very annoying.
>>>
>>> A simple way to solve it seems to make those options dependent on CONFIG_EXPERT.
>>>
>>> Not sure if all usual distributions disable it, but I guess most won't have
>>> EXPERT enabled.
>>>
>>> The enclosed patch does that. If nobody complains, I'll submit it together
>>> with the next git pull request.
>>>
>>> Regards,
>>> Mauro
>>>
>>> -
>>>
>>> [RFC PATCH] Make tuner/frontend options dependent on EXPERT
>>>
>>> The media CUSTOMISE options are there to allow embedded systems and advanced
>>> users to disable tuner/frontends that are supported by a bridge driver to
>>> be disabled, in order to save some disk space and memory, when compiled builtin.
>>>
>>> However, distros are mistakenly enabling it, causing problems when a
>>> make oldconfig is used.
>>>
>>> Make those options dependent on EXPERT, in order to avoid such annoyance behavior.
>>>
>>> Signed-off-by: Mauro Carvalho Chehab <mchehab@...hat.com>
>>>
>>> diff --git a/drivers/media/common/tuners/Kconfig b/drivers/media/common/tuners/Kconfig
>>> index bbf4945..702a3bf 100644
>>> --- a/drivers/media/common/tuners/Kconfig
>>> +++ b/drivers/media/common/tuners/Kconfig
>>> @@ -35,6 +35,7 @@ config MEDIA_TUNER
>>>  config MEDIA_TUNER_CUSTOMISE
>>>  	bool "Customize analog and hybrid tuner modules to build"
>>>  	depends on MEDIA_TUNER
>>> +	depends on EXPERT
>>>  	default y if EXPERT
>>         ^^^^^^^^^^^^^^^^^^^
>>
>> Hmm, why should CONFIG_EXPERT automatically mean that the tuner modules
>> should be customized? I'd think this shouldn't default to y even with
>> EXPERT.
>>
>> Not a biggie, just thought I'd point it out :)
>>
>> (as a sidenote, on Mageia kernels CONFIG_EXPERT is on... didn't check
>> why, could be just historical reasons)
>>
>>>  	help
>>>  	  This allows the user to deselect tuner drivers unnecessary
>>> diff --git a/drivers/media/dvb/frontends/Kconfig b/drivers/media/dvb/frontends/Kconfig
>>> index b98ebb2..6d3c2f7 100644
>>> --- a/drivers/media/dvb/frontends/Kconfig
>>> +++ b/drivers/media/dvb/frontends/Kconfig
>>> @@ -1,6 +1,7 @@
>>>  config DVB_FE_CUSTOMISE
>>>  	bool "Customise the frontend modules to build"
>>>  	depends on DVB_CORE
>>> +	depends on EXPERT
>>>  	default y if EXPERT
>>
>> Ditto.
>>
>>>  	help
>>>  	  This allows the user to select/deselect frontend drivers for their
>>
> 
> This was added on the changeset b3fc1782c8 (see below). A latter changeset (6a108a14fa3)
> renamed EMBEDDED to EXPERT.
> 
> For embedded systems, it makes more sense to customize the tuners/demods, in order to
> remove drivers that would never be used there. That's the rationale behind this patch.
> 
> From my side, I don't mind removing the "default y if EXPERT", but, as I don't usually
> work with embedded devices, I don't care much about that. It would be great to hear
> some comments from embedded people about that as well.

OK.

> That's said, it is weird that Mageia is using CONFIG_EXPERT. Are they using those
> two Kconfig options enabled as well?

No, *_CUSTOMISE are unset. CC'd our kernel maintainer in case he
remembers off-hand why CONFIG_EXPERT is enabled.


> Regards,
> Mauro
> 
> -
> 
> commit b3fc1782c8b84574e44cf5869c9afa75523e2db8
> Author: Guennadi Liakhovetski <lyakh@...ensa5220.grange>
> Date:   Thu Aug 5 18:09:28 2010 -0300
> 
>     V4L/DVB: V4L: do not autoselect components on embedded systems
>     
>     Tuner, DVB frontend and video helper chip drivers are by default
>     autoselected by their respective host cards, this, however, doesn't make
>     much sense on SoC-based systems. Disable autoselection on EMBEDDED
>     systems.
>     
>     Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@....de>
>     Signed-off-by: Mauro Carvalho Chehab <mchehab@...hat.com>
[...]

-- 
Anssi Hannula
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