Focusrite Scarlett 8i6 silent input stream

Focusrite Scarlett 8i6 silent input stream

[ZTube]

I'm trying to get my Focusrite Scarlett 8i6 to run with alsa, however
while the sound output to the device works fine, the input does not and
merely delivers a silent stream. Since I can't find any reason for the
input stream to be completely silent I suspect this might be a driver bug.

$ arecord -D hw:0,0 -f S32_LE -r 48000 -c 10 | aplay

just results in complete silence


I'd be happy to provide more logs/detail if needed. Any idea what might
be going on?

Thanks,

ZTube

[alsa-info.sh] https://paste.debian.net/1236037/

Re: Focusrite Scarlett 8i6 silent input stream

[Claudio Cabral]

On Tue, Mar 29, 2022 at 07:18:11PM +0200, ZTube wrote:
> I'm trying to get my Focusrite Scarlett 8i6 to run with alsa, however
> while the sound output to the device works fine, the input does not and
> merely delivers a silent stream. Since I can't find any reason for the
> input stream to be completely silent I suspect this might be a driver bug.
Hi ZTube,

did you follow the setup instructions described here?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/usb/mixer_scarlett_gen2.c

There's also a bug with the saffire range currently that prevents
a record stream to be started after a playback stream.
I suspect the bug is related to the usb audio driver and the
handling of implicit feedback mode, but I haven't had the 
to confirm this yet.

Best,
Claudio Cabral
> 
> $ arecord -D hw:0,0 -f S32_LE -r 48000 -c 10 | aplay
> 
> just results in complete silence
> 
> 
> I'd be happy to provide more logs/detail if needed. Any idea what might
> be going on?
> 
> Thanks,
> 
> ZTube
> 
> [alsa-info.sh] https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpaste.debian.net%2F1236037%2F&data=04%7C01%7Cclca%40bang-olufsen.dk%7Cf4e40b9d3b5f495e60a208da11a84759%7C210d08b883f7470abc96381193ca14a1%7C0%7C0%7C637841711889888530%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=i5LZbJ9LT13EfOoMl5khr37s1aurziKkMLEl1dqPI5w%3D&reserved=0
> 

Re: Focusrite Scarlett 8i6 silent input stream

[Geoffrey D. Bennett]

Hi ZTube,

On Tue, Mar 29, 2022 at 07:18:11PM +0200, ZTube wrote:
> I'm trying to get my Focusrite Scarlett 8i6 to run with alsa,
> however while the sound output to the device works fine, the input
> does not and merely delivers a silent stream. Since I can't find any
> reason for the input stream to be completely silent I suspect this
> might be a driver bug.
> 
> $ arecord -D hw:0,0 -f S32_LE -r 48000 -c 10 | aplay
> 
> just results in complete silence
> 
> 
> I'd be happy to provide more logs/detail if needed. Any idea what
> might be going on?
> 
> Thanks,
> 
> ZTube
> 
> [alsa-info.sh] https://paste.debian.net/1236037/

In your also-info.sh output I noticed that you have the PCM 1 input
set to "Off", so if your Analogue 1 input is the only one with
anything plugged in to it, you will not get any audio.

You can fix this by changing the capture routing using "alsamixer
-cUSB". Set PCM 01 to Analogue 1.

Please check out the alsa-scarlett-gui that I recently released which
replaces alsamixer functionality for Scarlett Gen 2/3 devices, shows
the routing in a visual way, and lets you drag-and-drop connections:
https://github.com/geoffreybennett/alsa-scarlett-gui/

Another possible cause for your problem is reported here against
pipewire:
https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/1948 but it
seems that it could actually be an ALSA bug. See claudiocabral's
comment:

> I have the same issue on my 18i8. I've manged to reproduce it
> without using pipewire.
> 
> if I try to launch
> 
> aplay -D hw:USB -r 48000 -fS32_LE -c 8 /dev/zero
> 
> followed by
> 
> arecord -D hw:USB -r 48000 -fS32_LE -c20  out.wav
> 
> arecord fails with the message
> 
> arecord: set_params:1323: Broken configuration for this PCM: no
> configurations available
> 
> If I launch arecord first, both arecord and aplay work as intended.

Besides trying the above, you could also try downgrading your kernel
to 5.10 which apparently didn't have this problem.

Regards,
Geoffrey.