Need better instuctions for dahdi_dummy install

App_rpt-users
23

The attached pdf documents the procedure used to install the dahdi_dummy on my
AllStar Raspberry Pi Node.
.
Bill

ASL build dahdi_dummy…pdf (197.1 KB)

From: Brett Friermood via AllStarLink Discussion Groups noreply@community.allstarlink.org
Sent: Tuesday, April 21, 2020 3:40 PM
To: wllmbecks@gmail.com
Subject: [AllStarLink Discussion Groups] [App_rpt-users] Need better instuctions for dahdi_dummy install

Brett_Friermood
April 21

That’s what I just did.

I have a semi-working system on which I’m attempting to install dahdi_dummy. I’ve been working on setting it up for a while, and while the kernel packages were held per the README, “apt upgrade” had been run a number of times.

So, per your prior post regarding needing to have a fresh image, I removed the SD card and re-imaged it. Prior to placing the card back into the Pi and booting, I did a few housekeeping items such as copying my saved configuration files in and changing hostname.

First thing after booting the Pi and logging in, I held the kernel packages with apt-mark. I then installed the required packages per the wiki, which as you know required refreshing the repositories with “apt update”.

Attempting to build using make threw the same error of not having the correct kernel sources.

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In Reply To

wllmbecks1
April 21

Brett, It’s been a little while since I ran through this but. I recall that I did perform sudo apt-get update that’s needed to refresh the repository cache. However, do not perform any sudo apt-get upgrade steps until after you have successfully built the dhadi_dummy. Let me know if this doesn’t…

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1 Like
24

Thank You William, WA8WG. This seems to works. It seems to be installed according to ’ dahdi show status '.
I do not understand why when I try to run ’ dahdi_test ', it returns ’ permission denied '.

25

The /bin/sbin/dahdi_xxxx files are not executable by default.
To use any of the tools you’ll have to set the execution permission.

sudo chmod +x /usr/sbin/dahdi_test [Sets execution permission]
sudo dahdi_test [Executes the test]
Opened pseudo dahdi interface, measuring accuracy…
99.990% 99.980% 99.994% 99.994% 99.993% 99.993% 99.992% 99.992%
99.993% 99.990% 99.992% 99.992% ^C
— Results after 12 passes —
Best: 99.994% – Worst: 99.980% – Average: 99.991159%
Cumulative Accuracy (not per pass): 99.991
repeater@repeater:~ $

Bill

26

Any chance this dahdi workaround will be integrated into the official build? I have been bitten more than once by the problems of updating and broken dahdi. I just started fresh and will not update or upgrade EVER haha. I looked at the dahdi dummy method pdf you created and I am super gun shy to try it. I just want my system to keep working. I have not done a single update or upgrade. I was however pleasantly surprised at how fast I got a new image working. Thx.

27

I still haven’t figured out exactly why, but by following the steps in the PDF I was successful in updating it where it previously failed. I’m guessing there was a very small change in order of commands between my previous attempts and the outlined steps.

Since it was successful I’ve been working on other projects and haven’t spent the time to dig in to it. Even though it might be a pain, starting with a new image and following the steps exactly should work for you.

1 Like
28

I did it using the pdf created by WA8WG and it worked first try!! This was on a stock build that had already been fully set up and operational but never updated/upgraded. Only 2 issues I had was realizing what # to remove from the file and the other was the restart asterisk service command did not work. I restarted using the asl-menu.

One question I have is do I need to reverse/undo the first command? (that “holds” the headers- whatever that means…)
---->
sudo apt-mark hold raspberrypi-kernel-headers raspberrypi-kernel

29

bump- assume holding the headers should not be permanent?

30

Clifford,

Do not reverse sudo apt-mark hold raspberrypi-kernel-headers raspberrypi-kernel.

This step is important regardless if your platform requires the dahdi_dummy or not. It’s function is to preserve the original kernel driver base supporting URIx and similar USB radio interface hardware.

Failure to place them on hold will result in the loss of USB communications with said radio interface devices when performing routine apt-get upgrade operations.

My apology for the typo in the “how-to” (pdf) where I reversed two words in the command line to restart asterisk. That line should have read “sudo service asterisk restart” instead “sudo service restart asterisk”. But then I am getting old and it was quite late at night when I drafted the pdf. : )

Bill, WA8WG

31

Hmm I thought you also had to hold headers to stop DAHDI from getting broken. I am confused as to what the DAHDI dummy is for if headers/updates still need to be held back for DMK URI functioning. I have a URI but have not wired up a connector for it yet.

Late night ham radio projects- the best! haha thx again and appreciate the reply.

Clifford
KK6QMS

32

The DHDI dummy replicates a pseudo hardware clock that’s not available to DHADI when Asterisk is run on ARM (Raspberry Pi) processors that don’t offer hardware timing references common to Intel or AMD platforms.

The lack of a suitable timing reference usually results in audible stutter, but is not to be confused with other contributors of audio stutter effects. You first have to start with a stable clock source before you can diagnose and correct other impairments.

Bill

1 Like
33

thanks for the info much appreciated