https://bugzilla.kernel.org/show_bug.cgi?id=206519
--- Comment #3 from Shlomo (shlomo@fastmail.com) --- The bug first occurs in Arch Linux 5.5.arch1-1, which set CONFIG_DRM_AMD_DC_HDCP=y [1].
Arch Linux 5.4.15.arch1-1 is good. Arch Linux 5.4.15.arch1-1 with CONFIG_DRM_AMD_DC_HDCP=y set (and no other changes) is bad.
Arch Linux 5.5.arch1-1 (and later) is bad. (CONFIG_DRM_AMD_DC_HDCP=y is set)
Testing the most recent Arch Linux kernel shows the same: Arch Linux 5.5.3.arch1 is bad. Arch Linux 5.5.3.arch1 with CONFIG_DRM_AMD_DC_HDCP unset is good.
This means that this bug was triggered by changes to the config, not kernel changes, so I don't know if this is a regression or not.
[1] https://git.archlinux.org/svntogit/packages.git/commit/trunk?h=packages/linu...