From: =?utf-8?q?Hans-J=C3=BCrgen_Koch?= <hjk@linutronix.de>
Organization: Linutronix
To: Bernd Petrovitsch <bernd@firmix.at>
Subject: Re: [GIT PATCH] more Driver core patches for 2.6.19
Date: Thu, 14 Dec 2006 18:47:02 +0100
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References: <20061213195226.GA6736@kroah.com> <200612141056.03538.hjk@linutronix.de> <1166117658.28664.105.camel@tara.firmix.at>
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Am Donnerstag, 14. Dezember 2006 18:34 schrieb Bernd Petrovitsch:
> On Thu, 2006-12-14 at 10:56 +0100, Hans-Jürgen Koch wrote:
> [....]
> > A small German manufacturer produces high-end AD converter cards. He sells
> > 100 pieces per year, only in Germany and only with Windows drivers. He would
> > now like to make his cards work with Linux. He has two driver programmers
> > with little experience in writing Linux kernel drivers. What do you tell him?
> > Write a large kernel module from scratch? Completely rewrite his code 
> > because it uses floating point arithmetics?
> 
> Find a Linux kernel guru/company and pay him/them for
> -) an evaluation if it is "better" (for whatever better means) to port
> the driver
>      or write it from scratch and
> -) do the better thing.

Good idea - whatever "porting" means. There are lots of Windows drivers out there
that are also partly user space using that Kithara stuff. They have most of their
driver in a dll. So that is similar to what we want with UIO - except that we 
handle interrupts in a clean way, they don't.
If you need to port such a driver, simply writing a kernel module and a user space
library would change so much of the concept that you can start rewriting it from
scratch. And you'll have a large kernel module to maintain. OK, the guru/company
can earn money with it, at least as long as the customer doesn't realize it is
not the best solution for him.

Hans

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