# Kernel Downgrade to < 2.6.27 possible (for use of mISDN)

## mdesaive

Hello everybody,

I am now trying for some weeks to get Asterisk working with an HFC-USB ISDN adapter. The most preferable solution for me would be the mISDN drivers with asterisk-chan_misdn. But as I learned this does not work for recent Kernel Version since 2.6.27.

After several tries, I succeeded in installing the most recent mISDNuser system and chan_lcr sources from git to make the adapter accessible in Asterisk. But this way it looks as if I am not able to use the asterisk-gui to handle the configuration of the adapter. The gui seems only to know chan_misdn, not chan_lcr.

Questions:

Could it be a solution in my case to downgrade the kernel to a Version below 2.6.27 to use the mISDN System provided by portage? First problem with this idea: In my portage tree there are only kernel versions above 2.6.32 available. 

Would it break my system to downgrade to a kernel version below 2.6.27?

Is it possible to get an ebuild for this kernel version, so that I can have the kernel registered for my system with eselect? Or should I just try to download some kernel sources from kernel.org? 

For example: ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.26.8.tar.bz2

compile it, install it, an run my gentoo system with that kernel?

Really looking forward for some advice in this issue!

Thanks a lot and best greetings from Berlin,

Melanie

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## solamour

I once did something similar, although I'm not sure it's applicable to your case. For some (unknown) reasons, one of my old box refused to work with anything newer than "suspend2-sources-2.6.15-r7" kernel, which wasn't in the portage anymore due to its old age.

I was able to find the "dead" files at http://sources.gentoo.org/viewcvs.py/gentoo-x86/sys-kernel/suspend2-sources/files/digest-suspend2-sources-2.6.15-r7?hideattic=0&rev=1.2&view=log

What I needed were 1) ebuild file, 2) digest file, and 3) actual source code.

1) http://sources.gentoo.org/viewcvs.py/*checkout*/gentoo-x86/sys-kernel/suspend2-sources/suspend2-sources-2.6.15-r7.ebuild

   Put it in "/usr/portage/sys-kernel/suspend2-sources/suspend2-sources-2.6.15-r7.ebuild"

2) http://sources.gentoo.org/viewcvs.py/*checkout*/gentoo-x86/sys-kernel/suspend2-sources/files/digest-suspend2-sources-2.6.15-r7

   Put it in "/usr/portage/sys-kernel/suspend2-sources/files/digest-suspend2-sources-2.6.15-r7"

3) Check the digest file and decide what files are needed. In my case I needed to put the files in the following location.

      /usr/portage/distfiles/genpatches-2.6.15-9.base.tar.bz2

      /usr/portage/distfiles/genpatches-2.6.15-9.extras.tar.bz2

      /usr/portage/distfiles/linux-2.6.15.tar.bz2

      /usr/portage/distfiles/suspend2-2.2-for-2.6.15.1.tar.bz2

After that, it's just a matter of emerging with some restrictions.

ACCEPT_KEYWORDS="~x86" emerge =sys-kernel/suspend2-sources-2.6.15-r7

__

sol

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## Hu

Although you may be able to obtain and start such an old kernel, some software on your system will likely not work well.  In particular, modern udev is not well supported on such old kernels.  Could you explain why such an old kernel is required to use your hardware?

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## mdesaive

Hello,

I would like to use an ISDN-USB Adapter for Asterisk. For that reason I would like to in emerge aterisk-chan_misdn with Asterisk. Asterisk-chan_misnd depends on mISDN and mISDN user, which don't compile for kernels >= 2.6.27. If I understand correctly, the reason for that is, that from kernel 2.6.27 the mISDN was integrated into the kernel and the mISDN ebuild became obsolete.

See "Bug 265581 - net-dialup/misdn-1.1.7.2 won't compile with kernel >= 2.6.27" (https://bugs.gentoo.org/265581?id=265581).

I succeeded to get the ISDN Adapter working with the following software:

  - mISDN System in kernel 2.6.39 (no additional compiling of mISDN sources)

  - mISDNuser from http://www.linux-call-router.de/download/lcr-1.7/mISDNuser-20100525.tar.gz

  - LCR from git - but there I had to figure out only the branch 1.8 compiled for my system. (git clone -b 1.8 git://git.misdn.org/lcr.git)

  - Asterisk 1.6.2.18.2 from portage

Two reasons, why I would like to know if a kernel downgrade to < 2.6.27 would be working:

For the solution with chan_lcr I am really quite afraid, that it might be unstable, because it was quite a lot of guessing and trying to get those versions together to compile. If it comes out, that it is not working correctly, I would like to know if a kernel downgrade and installation of chan_misdn would be a solution.

I really would like to use asterisk-gui for the system. This doesn't seem to recognise the ISDN adapter, when it is provided by lcr. I would be much nicer to have the isdn adapter available for configuration through the gui. I would like to have a try, if this would work with chan_misdn. (But this is not really the most important reason, it should also be alright, to configure the trunk manually.)

Thanks a lot for your help,

Greetings,

Melanie

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## VoidMage

What was the exact way you've built that set ?

Are you sure you've built everything you've wanted and then installed it where other components can find it ?

While the docs are hard to google, asterisk should have tools for lcr (or is that only a gui problem ?).

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## mdesaive

The way I compiled everything, I am able to dial out with one SIP phone on the inside through the ISDN line to the outside world and to receive calls the other way by using a simple handmade configuration.

Maybe I should just be confident with this solution: The gui works - I can use it to configure various parameters of asterisk. Only the ISDN hardware is not regognised. And I guess this is, because asterisk-chan_lcr it is just not supported by the gui.

But somehow I am not confident with this solution:

I really would like to have the complete configuration of all necessary parameters managemed by asterisk-gui. 

And also would like to use software which is regularly in portage, so I can update it easily.

I already thought about buying a fritzcard-usb and try to use the capi-drivers to connect it to asterisk. But if I get stuck after paying lots of money for the new hardware and don't have a better solution than before I would really be stupid!

Maybe I sleep over it on the weekend and decide on Monday in what direction to continue working. 

1) Using actual solution with chan_lcr

2) Kernel Downgrade and using chan_mISDN

3) FritzCardUsb and chan_capi

Greetings,

Melanie

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