[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <4820B524.5080100@s5r6.in-berlin.de>
Date: Tue, 06 May 2008 21:44:36 +0200
From: Stefan Richter <stefanr@...6.in-berlin.de>
To: Mauro Carvalho Chehab <mchehab@...radead.org>
CC: Alistair John Strachan <alistair@...zero.co.uk>,
Robin Holt <holt@....com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Linux 2.6.26-rc1
Mauro Carvalho Chehab wrote:
> On Tue, 06 May 2008 16:34:27 +0200
> Stefan Richter <stefanr@...6.in-berlin.de> wrote:
>> But it is /trivial/ to fix. If A selects B, you have to copy all of B's
>> dependencies to A or select these dependencies by A.
>>
>> So it's totally simple to do it right. The only nuisance is that you
>> always have to update B's dependencies and selections whenever A's
>> dependencies are changed.
>
> This is easy to maintain, if you have just a few selects, but this is not the
> case of V4L drivers. Look some examples:
>
> IVTV driver:
[...]
> You may argue to not use select, but it is really hard to avoid, since each of
> those main drivers (cx88, ivtv, bttv, etc) supports a large number of different
> devices, that needs different chips. Most V4L/DVB devices has an internal I2C
> bus that gives the flexibility for the board manufacturers to add/replace the
> internal components at the i2c bus. So, the Kernel uses abstraction layers that
> allows that the same driver to use different internal components.
Shouldn't layers actually untangle dependencies, i.e. concentrate
dependencies? A "high-level driver" does not depend on "low-level
drivers" and the low-level drivers' dependencies anymore. It only
depends on a "core driver" and on foreign subsystem APIs.
And yes, the core driver may very well provide some functionality which
not all of the high-level drivers need, or not all of the low-level
drivers are able to support.
(All theoretical since I have no idea of what kinds of modules of
functionality you have/need and whether it really can be simpler organized.)
--
Stefan Richter
-=====-==--- -=-= --==-
http://arcgraph.de/sr/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists