LinuxMusicians

As far as I understood for the changes to be merged they shouldn't break duplex on ALSA like they're doing it now. To be able to achieve that some usb_audio changes are needed too.
So currently this patch is a workaround and not a fix because it breaks "normal" workflow on ALSA/PulseAudio.

lapsio wrote: ↑Tue Jun 09, 2020 7:37 pm I think at this point more than enough people confirmed those fixes work properly

They didn't. Applying that patch breaks audio duplex in ALSA and PulseAudio. I don't think it'll end in upstream before implicit feedback problem is solved too.

lilith wrote: ↑Mon Jun 01, 2020 6:01 pm So, in my case it depends on the cable.

Without the patch I had different amount of crackling sounds per minute on different cables or when using different ports.

Updated patch. Added Scarlett 18i8 3rd Gen. Also slightly changed the way to get altsetting. Tested on my 18i20 gen3 too. Works fine. No crackling. Didn't check if duplex is working on default PulseAudio setup though. Didn't see any news about fixing implicit feedback so I think that it's still not...

Martin79 , alex , this topic (and forum) is not about kernel building. You should probably start with some docs about building the kernel in your distro. For example I've found some links in the Google ("ubuntu build kernel with patches"): https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel...

I've improved debug output. Could you try the new patch? Apr 17 22:13:13 skobkin-pc kernel: usb 5-2: 1:1 : max rate validation failed: 33629200 / 2012410 Apr 17 22:13:13 skobkin-pc kernel: usb 5-2: 1:1 : max rate validation failed: 33629200 / 2012410 Apr 17 22:13:13 skobkin-pc kernel: usb 5-2: 1:1 ...

Do you see messages like "max rate validation error" in dmesg? # lsusb | fgrep Focusrite Bus 001 Device 002: ID 1235:8215 Focusrite-Novation Scarlett 18i20 USB # journalctl -b -k | fgrep -A3 -B3 'max rate' Apr 16 19:16:01 skobkin-pc kernel: hid-generic 0003:04B4:0510.0004: input,hidraw3: ...

Just applied both patches and tested how they're working. 1. Crackling fix. Well, at least playback will be glitch-free. :) Note: earlier I discovered that I'm getting different amount of sound distortions when using different USB ports. And then I ended using the port which caused least crackling. ...

Note that full duplex mode will work only with jack due to some limitations in the driver. So if I'm using PulseAudio right now there is nothing for me to improve in the current situation by these patches? I was planning to check if wiring PulseAudio through Jack would work but hadn't much time to ...

Correct. But instead of an old patch against quirks-table.h please try the attached patch. It should apply cleanly at least to 5.4-5.6 kernels. Ok. What about this part from the first two pages? --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -365,6 +365,10 @@ static int set_sync_ep_implicit_fb_quir...

if i lower the frames number, i can get cracks on complex songs. How complex? I'm asking because you will get crackling even on Windows where it works like intended if you use small buffer size with many VST plugins. That's why it's a common practice to record on small buffer size to avoid latency ...

Hi! Recently I've found that Focusrite implemented multiple channel support for Windows (WDM) and now you can see all your outputs and inputs in the same way you configured them in the Focusrite Control. That's what I'm missing in Linux/PulseAudio now. Not sure if it can help but if it is, then you ...