Looks like kernel 6.17 has truly deprecated the EXTRA_CFLAGS and hence the Ubuntu 24.04 package for building the module is now broken if using the HWE kernel.
I can see exactly what needs to be updated in the Kbuild file, but I haven’t done enough packaging to have a clean solution. Here’s the difference between the newer Kbuild scripts (570) and the Kbuild script in 550.163.01 (which I’m currently stuck on due to these freezes):
kbuild.patch.txt (2.8 KB)
Turns out, there has also been a change to the interface of drm_helper_mode_fill_fb_struct and possibly some others. I’ll see if I can backport the smallest set of changes from 580 to patch this, too.