On Tue, 08 Dec 2020 11:15:08 +0100, meschi@xxxxxxxxx wrote: > > Hi, > > I am using a Steinberg UR22 audio interface. Since installing Ubuntu > 20.04 on my workstation I have slight crackling in audio playback. It > doesn't matter if the audio gets routed through pulse, jack or played > straight to alsa. When running jack, the crackling is not showing any > xruns. It's not possible to get any glitch-free playback in the > system. The onboard intel audio works fine. > > My system: > > alsa info: > alsa-project.org/db/?f=8b821b17a8c83fa5db866f34a5b4dfe74d640a32 > > Processor: Intel Xeon X5687 > > $ uname -a > > Linux WorkStation-T5500 5.4.0-56-lowlatency #62-Ubuntu SMP PREEMPT Mon > Nov 23 20:19:44 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux > > > > I have tried: > > 5.4.0-56-generic and -lowlatency > > 5.8.0-31-generic and -lowlatency > > setting cpu governor to performance > > using nouveau driver over nvidia > > > > When playing a file with aplay like this: > > systemctl --user stop pulseaudio.socket > systemctl --user stop pulseaudio.service > aplay -D plughw:CARD=UR22 ./test.wav > > > > slight crackling can be heard every 5-10 seconds. It also appears, > that the clicks heard are not always on both channels, sometimes the > left stereo channel clicks, sometimes the right, sometimes both. > > > > Plugging the Interface into different USB-ports doesn't help. The only > external devices connected via USB are my mouse and my keyboard. On > Wndows the same setup on the same machine works fine. > > To make things even weirder, using the same audio interface on my > Thinkpad x220 (Core i5-2540M) with ubuntu 20.04 and > 5.4.0.56-lowlatency does not show this problem. > > > > Running dmesg seems to show nothing audio driver related after: > > [ 22.425520] usbcore: registered new interface driver snd-usb-audio > > > > I have found a similar issue showcasing the problem on manjaro with a > differend soundcard. Therefore I suspect the problem is caused by ALSA > interacting with the hardware. > > https://forum.manjaro.org/t/pops-clicks-on-audio-interface/40129 > > > > Here is another occurence on ubuntu on yet another audio interface. > > https://askubuntu.com/questions/1256787/ubuntu-2004-novation-xiosynth-external-usb-audio-interface-producing-popping > > > > If I can supply more information I'm happy to help. I couldn't find a > similar issue in this mailing list, so if this is already fixed I > apologize in advance. It's likely the issues with the implicit feedback. The latest development tree (either linux-next tree or topic/usb-audio-refactoring branch of my sound.git tree) contains the improvements of the implicit feedback mode. Takashi
