Re: Assistance getting the Universal Audio Apollo Solo USB to work with Linux

[Lars Melin <larsm17@gmail.com>]

On 2024-05-16 05:12, Ethin Probst wrote:
> On Sunday, May 12th, 2024 at 09:13, Alan Stern <stern@rowland.harvard.edu> wrote:
> 
>> ...
> 
>> Most likely, Windows sends some firmware to the device (which it needs
>> in order to run properly) and then restarts the device.
> 
> I don't believe this is happening after trying to dig into the
> captures a bit more. The firmware blobs that are in the archive are
> over 100000 bytes, and though there are some significantly large
> transfers, there isn't a single transfer that is the size of the
> firmware blob. I can't tell for certain though; VirtualBox truncated
> those large frames, so I'm uncertain what data is in them.

The .inf files in your drivers directory clearly tells the difference 
between the two USB Id's.
The description of 2b5a:000c is "UAD2 Arrow Firmware Loader" while the 
description for 2b5a:000d is "Universal Audio Apollo Solo USB" so there 
is no doubt what the initial pid 000c is intended for.

There is nothing in your packet captures indicating a firmware transfer 
but that does not necessarily have to happen, there might just be a 
check of what firmware version is currently loaded in your audio 
hardware and if their isn't a more recent one in the firmware directory 
then everything is ok.

What puzzles me is your ua-init-windows.pcap, it starts with the device 
already having the pid 000d (packet #2). You said that the capture 
starts when the device is plugged in but I think you have missed 
something, it should have started as pid 000c and later transitioned to 
pid 000d.

I can also not find such a transition in your other two captures, all
descriptor readouts that includes USB Id are 2b5a:000c.


rgds
Lars