The fingerprint stack needs /dev/tee0, and the pmOS config has never built the
driver -- so every session so far has loaded an out-of-tree module. That has
been recorded since 2 September as the release blocker, on the reading that
drivers/tee/qcomtee/Kconfig's `select QCOM_TZMEM_MODE_SHMBRIDGE` would flip
tzmem out of Generic mode and drag a boot+selftest round with it.
It does not. QCOM_TZMEM_MODE_SHMBRIDGE is a member of a choice block, and
Kconfig cannot select a choice member -- the statement is inert, and silently
so. Setting CONFIG_QCOMTEE=m and running olddefconfig against the tree
produces exactly one line of difference and leaves CONFIG_QCOM_TZMEM_MODE_
GENERIC=y, which is the mode every fingerprint measurement was taken on.
The driver is already in the base tree; the only reason it was out-of-tree
here was that nothing enabled it. Verified on the dev phone: the module built
from this config carries ZERO module parameters against the research build's
95, matching vermagic, and the phone boots on it with modules-load.d bringing
it up, /dev/tee0 present, fingerprintd ready and the enrolled template
loading. So the shipped module is upstream code on the tested tzmem mode.
Not pushed. Whether to ship QCOMTEE with tzmem in Generic mode is a separate
question with a real answer -- journal/tee warns about that mode -- and it is
now sequenceable on its own instead of forced by a select that does nothing.
Jorijn van der Graaf
2da26cc42b