since 5.7.6 my elgato thunderbolt3 dock produces slow and distorted sound, for a video exactly showing this for kernel 5.8.x by another user, plz see 208311
i dont see this issue with kernel 5.6.19 btw
before the sound issues came up with 5.7.6, im pretty sure there was already something going on cause, i lost connection to a IR dongle for my keyboard that was plugged into the tb3 dock, removing it and pluging in again, froze my system more than once the past days (could have started with 5.75)
I have a Dell Thunderbolt WD19TB dock which connects my sound system via 3.5 mm plug and the same thing happened to me today when I upgraded from stock Arch kernel package 5.7.5 to 5.7.6. I switched back and forth a few times between those versions to confirm it.
I posted on the Arch forum about it at https://bbs.archlinux.org/viewtopic.php?pid=1912484.
I have exactly the same issue and setup as Mark Blakeney only that I am using a thinkpad and a Lenovo docking station.
I rebuilt my Arch 5.7.6 kernel with commit https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d288dc74f8cf95cb7ae0aaf245b7128627a49bf3 reverted and can confirm that the audio problem goes away.
I'm using a ThinkPad X1 Carbon Gen 8 with a ThinkPad Ultra Docking Station (40AJ) on Gentoo with Linux 5.7.6. Reverting the mentioned patch fixes the dock's audio port for external speakers for me, too.
Please let me know if / what debug info you need.
*** This bug has been marked as a duplicate of bug 208353 ***