In the Linux kernel, the following vulnerability has been resolved:
drm/i915/bios: Tolerate devdata==NULL in intelbiosencodersupportsdpdualmode()
If we have no VBT, or the VBT didn't declare the encoder in question, we won't have the 'devdata' for the encoder. Instead of oopsing just bail early.
We won't be able to tell whether the port is DP++ or not, but so be it.
(cherry picked from commit 26410896206342c8a80d2b027923e9ee7d33b733)