Subject: Kill I4L? (was: [PATCH 2/6] drivers: isdn: act2000: capi.c: fix checkpatch errors)

From: Tilman Schmidt <[email-masked]>
Date: Sun, 08 Feb 2015 20:47:22 +0100

Am 07.02.2015 um 21:43 schrieb Paul Bolle:
> On Sat, 2015-02-07 at 11:19 -0800, Joe Perches wrote:
>> Does anyone still use these cards?
> 
> 0) Good question.

I very much doubt it. It was an ISA card, not even PnP. I'd imagine
any systems of that kind would be retired by now.

> 2) Broader picture: if I remember correctly there are now four
> different flavors of ISDN in the kernel: - really old: pre-i4l

I don't think any traces of that are still present in current kernel
releases. It should all have been left behind on the switch to 2.6.

> - very old: i4l - just old: CAPI - not so old: mISDN

Those are the in-tree ones. To make matters worse, the Asterisk people
invented three more (Zaptel, DAHDI and vISDN) which are maintained
out-of-tree. Apparently they weren't satisfied with any the in-tree
ones and didn't feel like helping to improve one of them to match
their needs.

> [snip] So the current ISDN situation is a bit messy.

That's putting it mildly.

> Tilman might be able to provide a clearer, and maybe less grumpy, 
> summary of the current situation.

Don't know about either. ;-)

> [M]aybe we should consider, say, removing i4l and pre i4l and see
> who complains. That might be a rude thing to do. So perhaps the 
> various ISDN flavors should be left alone until ... what exactly?

I'd support that step. I don't think it'll hurt anyone because the
cards supported by i4l are mostly ISA cards anyway. The only exceptions
are the HiSax family which is now supported by mISDN, and the Hypercope
family which is supported by CAPI.

In the past we had Documentation/feature-removal-schedule.txt for
announcing removals like that but Linus shot that down on 2012-10-01
(commit 9c0ece069b32e8e122aea71aa47181c10eb85ba7) so I guess
somebody could just submit a patch series starting with

- --- a/drivers/isdn/Kconfig
+++ b/drivers/isdn/Kconfig
@@ -20,25 +20,6 @@ menuconfig ISDN

 if ISDN

- -menuconfig ISDN_I4L
- -       tristate "Old ISDN4Linux (deprecated)"
- -       depends on TTY
- -       ---help---
- -         This driver allows you to use an ISDN adapter for networking
- -         connections and as dialin/out device.  The isdn-tty's have a
built
- -         in AT-compatible modem emulator.  Network devices support
autodial,
- -         channel-bundling, callback and caller-authentication without
having
- -         a daemon running.  A reduced T.70 protocol is supported with
tty's
- -         suitable for German BTX.  On D-Channel, the protocols EDSS1
- -         (Euro-ISDN) and 1TR6 (German style) are supported.  See
- -         <file:Documentation/isdn/README> for more information.
- -
- -         ISDN support in the linux kernel is moving towards a new API,
- -         called CAPI (Common ISDN Application Programming Interface).
- -         Therefore the old ISDN4Linux layer will eventually become
obsolete.
- -         It is still available, though, for use with adapters that
are not
- -         supported by the new CAPI subsystem yet.
- -
 source "drivers/isdn/i4l/Kconfig"

 menuconfig ISDN_CAPI

and working its way from that to remove anything that's become
unreachable.

Shall I?

- -- 
Tilman Schmidt                              E-Mail: [email-masked]
Bonn, Germany
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