Comment # 18 on bug 1175908 from Harald Koenig

(In reply to Takashi Iwai from comment #15)
> I dunno, it depends on how it was encrypted.  We may check the crypt entries
> in the working case.

how can I provide this info?  

$ lsmod | egrep -i 'aes|crypt'
dm_crypt               49152  1
aesni_intel           372736  14
aes_x86_64             20480  1 aesni_intel
glue_helper            16384  1 aesni_intel
crypto_simd            16384  1 aesni_intel
cryptd                 24576  4 crypto_simd,ghash_clmulni_intel
dm_mod                155648  27
dm_crypt,dm_thin_pool,dm_multipath,dm_log,dm_mirror,dm_bufio

$ dmesg  | grep -i crypt
[    4.045430] Key type encrypted registered
[    4.959582] Freeing unused decrypted memory: 2040K
[    4.970846] systemd[1]: systemd 245.7+suse.49.g6d6d92930a running in system
mode. (+PAM -AUDIT +SELINUX -IMA +APPARMOR -SMACK +SYSVINIT +UTMP
+LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD
+IDN2 -IDN +PCRE2 default-hierarchy=hybrid)
[    5.055040] systemd[1]: Created slice system-systemd\x2dcryptsetup.slice.
[    5.993860] cryptd: max_cpu_qlen set to 1000
[   17.342901] systemd[1]: systemd 245.7+suse.49.g6d6d92930a running in system
mode. (+PAM -AUDIT +SELINUX -IMA +APPARMOR -SMACK +SYSVINIT +UTMP
+LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD
+IDN2 -IDN +PCRE2 default-hierarchy=hybrid)
[   17.670956] systemd[1]: Reached target Local Encrypted Volumes.

comparing list of all kernel mods in initrd (fully extracted including
compressed cpio in directory cpio-root-19000/
(left column: only in 5.3, right column: only in 5.8):

$ comm -3 <( find _initrd-5.3.12-2-default.extracted/ -name \*.ko\* |  sed
's,.*/,,' | sort -u ) <( find _initrd-5.8.4-1-default.extracted/ -name \*.ko\*
|  sed 's,.*/,,' | sort -u )
aes-x86_64.ko.xz
        battery.ko.xz
        cec.ko.xz
        fsl_linflexuart.ko.xz
        hid-creative-sb0540.ko.xz
        hid-glorious.ko.xz
        hid-lg-g15.ko.xz
        hid-mcp2221.ko.xz
input-polldev.ko.xz
        iqs62x-keys.ko.xz
        iqs62x.ko.xz
        lantiq.ko.xz
        pci-hyperv-intf.ko.xz
        pinctrl-da9062.ko.xz
        pinctrl-jasperlake.ko.xz
        pinctrl-lynxpoint.ko.xz
        pinctrl-tigerlake.ko.xz
        regmap-spi.ko.xz
        sprd_serial.ko.xz
xen-blkfront.ko.xz
xen-netfront.ko.xz
        xhci-pci-renesas.ko.xz
        xhci-plat-hcd.ko.xz


could it be aes-x86_64.ko.xz ???

$ find -name aes-x86_64.ko.xz
./_initrd-5.3.12-2-default.extracted/cpio-root-19000/lib/modules/5.3.12-2-default/kernel/arch/x86/crypto/aes-x86_64.ko.xz

this module is *not* available in 5.8 anymore:

$ find /lib/modules/5.8.4-1-default/  -name aes-x86_64.ko.xz
$ find /lib/modules/5.8.4-1-default/  -name aes\*.ko.xz
/lib/modules/5.8.4-1-default/kernel/arch/x86/crypto/aesni-intel.ko.xz
/lib/modules/5.8.4-1-default/kernel/crypto/aes_ti.ko.xz


for next reboot I'll try an initrc created with

dracut --kver 5.8.4-1-default --force  --install "/sbin/cryptsetup" --install 
/lib/modules/5.8.4-1-default/kernel/crypto/aes_ti.ko.xz --install
/lib/modules/5.8.4-1-default/kernel/arch/x86/crypto/aesni-intel.ko.xz

cross fingers... ;-)