Stacato audio on DVSM


Steve N4IRS
 

Since SystemBuilder did not include AMBEServer, it's not really part o the process. Not at least at this time.

On 9/5/20 6:07 AM, Derek William Haden wrote:

I added the line

ExecStartPre = /bin/sh -c 'echo "1" >> /sys/bus/usb-serial/devices/ttyUSB0/latency_timer'

To the systemd unit file and enabled the service, and all is now working fine.

I guess another snippet of information to add to the install process.

Again, many thanks for the help.



Derek William Haden <facebook@...>
 

I added the line

ExecStartPre = /bin/sh -c 'echo "1" >> /sys/bus/usb-serial/devices/ttyUSB0/latency_timer'

To the systemd unit file and enabled the service, and all is now working fine.

I guess another snippet of information to add to the install process.

Again, many thanks for the help.


Derek William Haden <facebook@...>
 

yes, the ambeserver is started by a systemd unit file.

I am out most of day tomorrow, but will give it a try before the weekend.

again thanks for all the help.


Steve N4IRS
 

I don't know if you use a systemd unit file to start/stop/restart your AMBEServer.
If you do, You could add:
ExecStartPre = /bin/sh -c 'echo "1" >> /sys/bus/usb-serial/devices/ttyUSB0/latency_timer'

to the [SERVICE] stanza in the unit file that controls AMBEServer

On 9/2/2020 10:34 AM, Derek William Haden wrote:

OK if I restart everything, from fresh reboot, with AB configured for ambe server, but ambe server not yet started.
stop AB
do echo 1 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer

start amber server and restart AB

all seems to work correctly I do not get the stacato audio.

So I am guessing that somehow the command echo 1 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
Needs to to part of the ambe server start up? which I have no idea how to do.



Derek William Haden <facebook@...>
 

OK if I restart everything, from fresh reboot, with AB configured for ambe server, but ambe server not yet started.
stop AB
do echo 1 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer

start amber server and restart AB

all seems to work correctly I do not get the stacato audio.

So I am guessing that somehow the command echo 1 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
Needs to to part of the ambe server start up? which I have no idea how to do.


Steve N4IRS
 

sudo -s
echo 1 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer


On 8/30/20 4:40 AM, Derek William Haden wrote:
OK
AB set for Ambeserver, but server not started

cat returns 1

AB set for Ambeserver,
Rebooted
server started
cat returns 16

stopped ambeserver

and tried to run echo 1 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer

however even with sudo I get permission denied



Derek William Haden <facebook@...>
 

The DVLink image works fine, the only difference I can think of is that on the DVLink image I installed the amber server from

https://nw-digital-radio.groups.io/g/ambe/topic/how_to_install_ambeserver_on/25743616?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,25743616

On the DVSwitch image I used

https://github.com/nwdigitalradio/ambeserver-install

could this have any bearing on the problem?


Derek William Haden <facebook@...>
 

OK
AB set for Ambeserver, but server not started

cat returns 1

AB set for Ambeserver,
Rebooted
server started
cat returns 16

stopped ambeserver

and tried to run echo 1 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer

however even with sudo I get permission denied


Steve N4IRS
 

Is Analog_Bridge reconfigured to use AMBEServer?
stop AMBEServer:
echo 1 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer

start AMBEServer
retest.

On 8/29/20 8:21 AM, Derek William Haden wrote:
When I ran "cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer"

when running ambe server it was 16

disabling the ambe server the output is 1


Steve N4IRS
 

As I said, we were not done yet. It does prove where the issue is.
Put Analog_Bridge.ini back to using AMBEServer
stop AMBEServer
Show me the output of "cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer"


On 8/29/20 8:19 AM, Derek William Haden wrote:
Well that works fine, disabled the ambe server and just went direct to the dongle.

using ambe-server seems a more elegant solution, as it means I can use Blue DV ambe also on another device.


Derek William Haden <facebook@...>
 

When I ran "cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer"

when running ambe server it was 16

disabling the ambe server the output is 1


Derek William Haden <facebook@...>
 

Well that works fine, disabled the ambe server and just went direct to the dongle.

using ambe-server seems a more elegant solution, as it means I can use Blue DV ambe also on another device.


Derek William Haden <facebook@...>
 

Steve

thanks for all your help so far.

I too am busy for a while, so this will have to wait.


Steve N4IRS
 

If not using AMBEServer works, then I suspect the serial latency is not set for optimal.

To verify this look at the output of:
cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
If the output is 16, that is a problem.

Analog_Bridge sets the for you, AMBEServer does not. If you revert to AMBEServer then before you start AMBEServer:
echo 1 >/sys/bus/usb-serial/devices/ttyUSB0/latency_timer

Then start AMBEServer and retest

I am out in the field today, so I will not have time to work with you on this today.

Steve N4IRS



On 8/27/20 2:42 PM, Derek William Haden wrote:
On Thu, Aug 27, 2020 at 10:22 AM, Steve N4IRS wrote:
I have one more thing to look at.
OK I'll try the none ambe server, then what?


Steve N4IRS
 

Leave AMBE server alone.
Show me the output of "cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer"

On 8/27/2020 2:42 PM, Derek William Haden wrote:
On Thu, Aug 27, 2020 at 10:22 AM, Steve N4IRS wrote:
I have one more thing to look at.
OK I'll try the none ambe server, then what?


Derek William Haden <facebook@...>
 

On Thu, Aug 27, 2020 at 10:22 AM, Steve N4IRS wrote:
I have one more thing to look at.
OK I'll try the none ambe server, then what?


Steve N4IRS
 

If you have not switched over direct yet you can try one quick thing.


On 8/27/2020 2:40 PM, Derek William Haden wrote:

So basically cutting out the middle man?

OK i'll look at it in the morning.



Derek William Haden <facebook@...>
 

I'll look at it in the morning.


Derek William Haden <facebook@...>
 

So basically cutting out the middle man?

OK i'll look at it in the morning.


Steve N4IRS
 

Do you have results from my last request? If so, I have one more thing to look at.

Steve N4IRS

On 8/27/2020 12:01 PM, Derek William Haden wrote:
Booted to console as you asked.
So running headless.
still same problem