Focusrite Scarlett 18i20 2nd Gen mixer driver

[geoffrey]

1. How is the driver enabled?

With module options "scarlett_gen2_mixer_enable=1" for v5.1.15s7 and "device_setup=1" for v5.2.2s9. The module will print the required option to the kernel log (seen with dmesg/journalctl) if it's not enabled. Although, I've found if you have more than one USB audio device you might need something like "device_setup=1,1,1,1" (I'm sure there's a better way to do this, but I don't know what it is).

2. Do you know, has the 2nd gen had many revisions?

I guess at least 2, but I have no idea really. All I know so far is that it seems interfaces with serial numbers 0003xxxx work and earlier serial numbers (beginning 1 or 2) don't work with this driver. And I still don't know why. I really hope we can find out before Linux 5.4 comes out & we can have the driver enabled by default!

[geoffrey]

Here is my usbmon output , lsusb -v -d some:id and dmesg as requested @geoffrey
I recon my 18i20 device is not the newest. But I ran out and downloaded the newest focusritepanelcontroll app/driver as soon as I bought device 1 month ago. I also, is an owner of focusrite octopre. I booted up in windows and did run factory defaults

Hi cjoke,

Thanks for that! I have looked at the output you provided and it's confirming my theory of devices with serial numbers < 00030000 not working with this driver. In order to make a driver that will work with these interfaces, I will need a USB trace showing how the Focusrite driver initialises the interface. To capture this trace you can use either a Linux host with the Focusrite Control software running in a VM or it looks like you could just capture it on a Windows host by using https://desowin.org/usbpcap/

If you're doing the trace on Linux, please use usbmon 6.1 from http://people.redhat.com/zaitcev/linux/ (capturing from the /sys usbmon file directly truncates the packets unfortunately).

Thanks,
Geoffrey.

[geoffrey]

FYI, I've now got the USB dump from the Focusrite driver initialising an older gen 2 interface that I was after. Hopefully I can do something good with it .

[xkr47]

So here's the link
https://tinyurl.com/yxbzjeo3

The link above shows javascript but if you edit the url to remove the ".js" at the end then you can access it just fine.

[xkr47]

geoffrey, how confident are you that you could get a 3rd gen scarlett working in Linux with access to usb dumps? I recall you wrote something about that earlier but couldn't find the post so..

[cjoke]

So here's the link
https://tinyurl.com/yxbzjeo3

The link above shows javascript but if you edit the url to remove the ".js" at the end then you can access it just fine.

Err, sorry for that, and thanks

[bluebell]

geoffrey, how confident are you that you could get a 3rd gen scarlett working in Linux with access to usb dumps? I recall you wrote something about that earlier but couldn't find the post so..

Since the 3rd gen Scarletts are shipped in Mass Storage Device mode (as their support informed me) it would be interesting if they can be used without connecting them to a Windows PC or Mac.

[geoffrey]

geoffrey, how confident are you that you could get a 3rd gen scarlett working in Linux with access to usb dumps? I recall you wrote something about that earlier but couldn't find the post so..

Hi xkr47,

I'm pretty confident that I *wouldn't* be able to do it from dumps only; I would need the interface in front of me. Even in the best case of the 3rd gen USB protocol having some similarities to the 2nd gen protocol, there must also be a lot of differences to cater for these new things I noticed browsing through the user guide: MSD mode, Air, Alt, Talkback, Loopback, the second optical port, and the different digital I/O modes.

Regards,
Geoffrey.

[geoffrey]

geoffrey, how confident are you that you could get a 3rd gen scarlett working in Linux with access to usb dumps? I recall you wrote something about that earlier but couldn't find the post so..

Since the 3rd gen Scarletts are shipped in Mass Storage Device mode (as their support informed me) it would be interesting if they can be used without connecting them to a Windows PC or Mac.

FWIW, the manual says you can take it out of MSD mode without running FC: "Initially, when in MSD mode, the interface will function at sample rates up to 48 kHz." "In order to force your Scarlett 18i20 out of MSD mode without first registering it, hold down the 1-4 48V button while disconnecting and reconnecting the USB cable, and then continue to hold the button down for a further five seconds."

[bluebell]

geoffrey, how confident are you that you could get a 3rd gen scarlett working in Linux with access to usb dumps? I recall you wrote something about that earlier but couldn't find the post so..

Since the 3rd gen Scarletts are shipped in Mass Storage Device mode (as their support informed me) it would be interesting if they can be used without connecting them to a Windows PC or Mac.

FWIW, the manual says you can take it out of MSD mode without running FC: "Initially, when in MSD mode, the interface will function at sample rates up to 48 kHz." "In order to force your Scarlett 18i20 out of MSD mode without first registering it, hold down the 1-4 48V button while disconnecting and reconnecting the USB cable, and then continue to hold the button down for a further five seconds."

Good news. Thanks.

[Jorin]

[...]
I will need a USB trace showing how the Focusrite driver initialises the interface. To capture this trace you can use either a Linux host with the Focusrite Control software running in a VM or it looks like you could just capture it on a Windows host by using https://desowin.org/usbpcap/
[...]

Hey Geoffrey! I'm running into some trouble with my 18i20 and it reports serial 0001xxx in the Windows Focusrite Control app, so I'm guessing the issue might be related. I set up wireshark tonight but I'm too tired to figure usage out. Going to give it another try tomorrow. I haven't used wireshark before. so if you could give me some precise pointers that'd be perfect

Edit: I hope I've made a successful capture! You can grab it here
https://butt.melatonin.fun/s/5cwyek9pB3AT5A6
My SSL certificate expired so I do apologise if I haven't fixed it by the time you download the file.

Edit 2: updated the Focusrite software, which fixed some issues I was having with 88.2kHz and 96kHz. So most likely, whatever the software was doing in the previous log was wrong. I'm still having trouble with above 96kHz but this is most likely a different issue as the card supposedly has to restrict some features in order to run at that rate. See the new capture here:
https://butt.melatonin.fun/s/66bzeTGmc9sQZqJ

[Lani]

Hi? I downloaded Sources Code.zip from Test6 Assets. Can you tell me how to install?

https://github.com/geoffreybennett/scar ... g/v5.2.2s9

[Jorin]

Hi? I downloaded Sources Code.zip from Test6 Assets. Can you tell me how to install?

https://github.com/geoffreybennett/scar ... g/v5.2.2s9

You will need to compile the kernel. It's not too hard, though it can be a bit daunting. Specifics might vary between distributions. Here's an example for how to do so on Ubuntu:
https://www.linux.com/learn/intro-to-li ... x-kernel-0

The Arch Linux wiki has an excellent article for it as well:
https://wiki.archlinux.org/index.php/Ke ... ompilation