We load the Thunderbolt controller firmware to see if the controller is in
native mode, as this changes the GUID. If the controller is asleep the firmware
is not cached by the kernel and it can take more than 4 seconds to read out
504kB of firmware.
We only need the first two 64-byte chunks, so only read what is required.
This speeds up fwupd starting substantially, and also means we don't have to
allocate a giant chunk of heap memory just to inspect one byte.
Fixes: https://github.com/hughsie/fwupd/issues/848
Kernel v4.15 added support for native enumeration of Thunderbolt
topology. The enumeration mode affects both the BIOS and TBT FW
operation so they must agree on it. Platforms may support both modes,
native and "legacy" (or "BIOS-assist").
This change makes sure the new image is compatible with the current
controller mode (otherwise the BIOS and TBT FW will not be alligned on
it at least until next boot) and also adds a new GUID generation logic
for a controller in "native" mode so LVFS could contain 2 images, one for
the "legacy" mode and one for "native".
Signed-off-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
