Re: Digital-tv card drivers and API discussion

From: Eivind Eklund (eivind_at_FreeBSD.org)
Date: 04/13/04

  • Next message: Teemu.Parkkinen_at_patria.fi: "Re: Digital-tv card drivers and API discussion" 
    Date: Tue, 13 Apr 2004 10:41:28 +0000
To: Teemu.Parkkinen@patria.fi

    On Tue, Apr 13, 2004 at 12:44:35PM +0300, Teemu.Parkkinen@patria.fi wrote:
    > Hi all,
    >
    > I am about to write a digital tv-driver for my dvb-c -card.

    [...]

    > 1) Should we use Linux-DVB API as a reference, or should we consider some
    > changes to it? The API seems to be constantly changing and improving.
    > Version 3 is available here:
    > http://www.linuxtv.org/download/dvb/linux-dvb-api-1.0.0.pdf
    > but they are currently working on version 4. In my opinion, the API should
    > be minimal, but complete, so there is no need to constantly add new
    > features to it.

    If the API in your evaluation is reasonably OK, we should stick with it
    (or a subset of it). Being directly compatible gives a lot of benefits.

    You may also want to look at the Brooktree (bktr) and Meteor (meteor)
    APIs already in FreeBSD. Ideally, all of these similar would be
    available through a single unified API, at least for the parts that are
    common.

    > 2) As linux kernel is GPL-licensed, I cannot just port the linux driver to
    > FreeBSD, right?

    That's more or less correct. We CAN port over drivers, but we really
    really prefer native (non-GPLed) drivers, as that lets us ship them
    compiled in, and allows the kind of re-use of the code that we want to
    allow.

    > In other words, we have to write the driver from scratch. In this case
    > we don't have to stick with the Linux DVB-API and therefore I suggest
    > that we give think the api through before deciding how we implement
    > it (do we follow linux api or not).

    What issues do you see with the Linux API that would make us want to
    change it?

    > 3) Do you have any pointers to good books or other documentation on how to
    > write device drivers for UNIX (BSD)? I already have read those from
    > FreeBSD documentation, but a decent book would be handy.

    The Design and Implementation of 4.4BSD contains some information, but
    it is getting somewhat dated - you need to check all information in it.

    Eivind.
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  • Next message: Teemu.Parkkinen_at_patria.fi: "Re: Digital-tv card drivers and API discussion"

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