https://bugzilla.kernel.org/show_bug.cgi?id=206519
--- Comment #4 from Shlomo (shlomo@fastmail.com) --- I bisected the bug.
The first bad commit is 96a3b32e67236f547cc8acd69d5a3cef125b2295 (drm/amd/display: only enable HDCP for DCN+) with ea268870d6f548d0661e896e9746673210c1fa79 (drm/amd/display: Add hdcp to Kconfig) cherry-picked on top of it.
(The previous commit da3fd7ac0bcf372cc57117bdfcd725cca7ef975a with ea268870d6f548d0661e896e9746673210c1fa79 cherry-picked on top of it is good.)
The call trace for this bug is the same as I posted above.