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DRAWS total failure Re: DRAWS audio crosstalk? #draws #direwolf


Brian Badger
 

Well, I changed it back but now the entire draws overlay is broken -- totally broken top to bottom.  No udrc audio device, no gps.

here is my entire /boot/config.txt

hdmi_force_hotplug=1

hdmi_group=2

hdmi_mode=82

force_turbo=1

dtoverlay=draws

#dtparam=audio=on


pi@compass
:~ $ aplay -l

 

aplay: device_list:270: no soundcards found...

pi@compass:~ $ ls /dev/ttySC0

 

ls: cannot access '/dev/ttySC0': No such file or directory

pi@compass:~ $ ls /dev/pps0

 

ls: cannot access '/dev/pps0': No such file or directory



Annaliese McDermond
 

You forgot the line

dtoverlay=

Before

dtoverlay=draws

You should have the following as the end of your file:

dtoverlay=
dtoverlay=draws
dtparam=audio=on

—Anna

On Dec 12, 2018, at 8:51 PM, Brian Badger <brian@...> wrote:

Well, I changed it back but now the entire draws overlay is broken -- totally broken top to bottom.  No udrc audio device, no gps.

here is my entire /boot/config.txt

hdmi_force_hotplug=1

hdmi_group=2

hdmi_mode=82

force_turbo=1

dtoverlay=draws

#dtparam=audio=on


pi@compass
:~ $ aplay -l

 

aplay: device_list:270: no soundcards found...

pi@compass:~ $ ls /dev/ttySC0

 

ls: cannot access '/dev/ttySC0': No such file or directory

pi@compass:~ $ ls /dev/pps0

 

ls: cannot access '/dev/pps0': No such file or directory



Brian Badger
 

Thank you for the help.  That resolved the issue.

Is there a configuration, installation, setup, or user guide document that you are referring to when you say "you forgot"?  I assure you "forgot" isn't the problem.  I can't forget something I don't know.  

I would love to know what else I don't know, but I can't find this stuff anywhere in the wiki.  

--
Brian N0KZ


Annaliese McDermond
 


On Dec 13, 2018, at 2:02 PM, Brian Badger <brian@...> wrote:

Thank you for the help.  That resolved the issue.

Is there a configuration, installation, setup, or user guide document that you are referring to when you say "you forgot"?  I assure you "forgot" isn't the problem.  I can't forget something I don't know.  

I’d have to demur to John on documentation as that’s more of his area. “Forgot” is probably a poor term. The only guide I’m referring to is my brain, but that’s because I’m the person who deals with drivers and systems integration.   I could explain about the device tree and the raspberry pi, but not tapping it out at work on my phone :)

I would love to know what else I don't know, but I can't find this stuff anywhere in the wiki.  

Much of this is standard raspian stuff. There is this thing called the device tree that describes the hardware to the Linux OS kernel. That’s what you’re playing with when you modify config.txt usually.   That’s all documented by the Pi foundation. 

—Anna



--
Brian N0KZ


Brian Badger
 

Anna,

I appreciate your time on this.  I have been using Raspbian for 5 years, with projects all through the house, but this is the first time I've seen an overlay work like this.  I have set dtparam=audio=on on other projects and it didn't come at the end.  When I was told to put dtparam=audio=on at the end, I was expecting the dtoverlay= to come after dtoverlay=draws since I assumed I had to close scope on the "draws" overlay in order to send a param to the main scope of the device tree. 

Instead it was exactly backwards of that in every respect.  My pi experience is working against me.

--

Brian N0KZ


 

I am not the expert, that would be Anna.

My understanding is that
dtoverlay=
is basically clearing the device tree overlay list, then you can add overlays with subsequent dtoverlay parameters like
dtoverlay=draws

My guess is that the dtparam=audio=on comes after the draws information as it is adding an audio driver to the device tree. 

This is not an invention of NW Digital Radio, it is from standard Raspbian.


On Thu, Dec 13, 2018 at 3:06 PM Brian Badger <brian@...> wrote:

Anna,

I appreciate your time on this.  I have been using Raspbian for 5 years, with projects all through the house, but this is the first time I've seen an overlay work like this.  I have set dtparam=audio=on on other projects and it didn't come at the end.  When I was told to put dtparam=audio=on at the end, I was expecting the dtoverlay= to come after dtoverlay=draws since I assumed I had to close scope on the "draws" overlay in order to send a param to the main scope of the device tree. 

Instead it was exactly backwards of that in every respect.  My pi experience is working against me.

--

Brian N0KZ



--


John D. Hays
Edmonds, WA
K7VE

   


Annaliese McDermond
 

On Dec 13, 2018, at 3:06 PM, Brian Badger <brian@...> wrote:

Anna,

I appreciate your time on this. I have been using Raspbian for 5 years, with projects all through the house, but this is the first time I've seen an overlay work like this. I have set dtparam=audio=on on other projects and it didn't come at the end. When I was told to put dtparam=audio=on at the end, I was expecting the dtoverlay= to come after dtoverlay=draws since I assumed I had to close scope on the "draws" overlay in order to send a param to the main scope of the device tree.

Instead it was exactly backwards of that in every respect. My pi experience is working against me.
In the HAT spec, there’s room to put a chunk of device tree on a flash chip on the hardware itself. If the firmware sees this, it will load up that device tree overlay and merge it with the rest of the stuff it happens to be doing. With the UDRC we did this, although with changes to the kernel the HAT-embedded device tree became invalid. I’m working on a field programmer for that, but I only have a certain number of amateur time units with which to work on this kinda thing.

What dtoverlay= does is clears out all device tree overlays whether they come from the HAT flash rom, or previous parameters in config.txt. We probably don’t really need it for the draws, but it’s absolutely necessary for udrc. Any dtoverlay/dtparam statements that come before this will essentially be ignored because dtoverlay= clears all of them out. So, you need to do the dtoverlay= first before you start loading other overlays or parameters. We would love to put the DRAWS overlay on the flash prom, but it slipped by us in testing that we’ve used a flash chip that’s too small to fit the overlay, hence you just have to use config.txt to load the overlay instead.

Hopefully that answers some of your questions about how the firmware loads all the DT stuff.

--

Brian N0KZ

--
Annaliese McDermond (NH6Z)
Xenotropic Systems
mcdermj@...