Rumor has it that the my USB ports powered by an AMD chipset might be the culprit. I have no clue whatsoever how this could be fixed in software, but I am now waiting for a PCIe USB card with a different chipset to check if there's a (preliminary) fix in hardware at least.
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to alsa-driver in Ubuntu. https://bugs.launchpad.net/bugs/1927255 Title: [USB-Audio - RODECaster Pro, playback] Sound is distorted (20.04) Status in alsa-driver package in Ubuntu: Confirmed Bug description: I got a Rodecaster Pro USB device that has been causing trouble before and already lead to quirk handling in the kernel for the sample rate, see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/usb/format.c?h=v5.8#n412 The Rodecaster is running fine on my laptop, but on my desktop, only audio input is working. The audio output is distorted. It's played kind of very slowly. Interestingly, if the source is a video file, the video plays slower, e.g. YouTube in a browser. I have never seen anything like that before. I have tried to figure out what the cause might be and I think I have reached the end of where I can get to on my own. I have documented most things at https://ubuntuforums.org/showthread.php?t=2461568 Putting my last step it in a nutshell: I have booted both my computers with a plain Ubuntu 21.04 from a pen drive (it uses kernel version 5.11.0-16-generic) to make sure it's not some different configuration that I have set up over the years on my systems (both Ubuntu 20.04 with kernel 5.8.18). I attached the Rodecaster. It runs fine on my laptop, but not on my desktop (used the output test from). I then detected the card number with aplay -l I killed pulseaudio with pulseaudio -k I then played the same sample (encoded in 48000 Hz in PCM signed 32 bit little endian format) using aplay -f S32_LE -c 2 -r 48000 -D hw:x ~/sample.wav where x is the appropriate card number and the rest of the arguments meet the Rodecaster's narrow specification. It's playing fine on the laptop, but distorted on the desktop. As far as I understand using aplay this way without a plugin should send the file directly to the device, so I assume there's something on the way from aplay to the Rodecaster that's interfering (kernel or even some piece of hardware) - and that definitely is where my expertise ends (rather a little before :-)). I'll gladly contribute any information that could be useful and I will willingly help to debug this problem if it may be related to the kernel. If there's anything I can do, please let me know. Cheers, Oliver ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: alsa-base 1.0.25+dfsg-0ubuntu5 Uname: Linux 5.8.18-050818-generic x86_64 NonfreeKernelModules: blackmagic_io nvidia_modeset nvidia ApportVersion: 2.20.11-0ubuntu27.16 Architecture: amd64 CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME CurrentDmesg: Error: command ['dmesg'] failed with exit code 1: dmesg: read kernel buffer failed: Operation not permitted Date: Wed May 5 18:28:46 2021 InstallationDate: Installed on 2020-05-15 (355 days ago) InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423) PackageArchitecture: all SourcePackage: alsa-driver Symptom: audio Symptom_AlsaPlaybackTest: ALSA playback test through plughw:Pro failed Symptom_Card: RODECaster Pro - RODECaster Pro Symptom_Type: Digital clip or distortion, or "overdriven" sound Title: [USB-Audio - RODECaster Pro, playback] Sound is distorted UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/30/2020 dmi.bios.release: 5.17 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: A.40 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: B550-A PRO (MS-7C56) dmi.board.vendor: Micro-Star International Co., Ltd. dmi.board.version: 1.0 dmi.chassis.asset.tag: To be filled by O.E.M. dmi.chassis.type: 3 dmi.chassis.vendor: Micro-Star International Co., Ltd. dmi.chassis.version: 1.0 dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrA.40:bd10/30/2020:br5.17:svnMicro-StarInternationalCo.,Ltd.:pnMS-7C56:pvr1.0:rvnMicro-StarInternationalCo.,Ltd.:rnB550-APRO(MS-7C56):rvr1.0:cvnMicro-StarInternationalCo.,Ltd.:ct3:cvr1.0: dmi.product.family: To be filled by O.E.M. dmi.product.name: MS-7C56 dmi.product.sku: To be filled by O.E.M. dmi.product.version: 1.0 dmi.sys.vendor: Micro-Star International Co., Ltd. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1927255/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
