https://bugs.freedesktop.org/show_bug.cgi?id=92858
--- Comment #7 from Darren D. ysxikrhn@vomoto.com --- (In reply to Michel Dänzer from comment #6)
(In reply to Darren from comment #5)
Sadly, as of thus far, every kernel I've compiled panics at bootup, with a message like this, or similar: "kernel panic. vfs unable to mount root on unknown block (0,0)".
Sounds like there's a problem with the .config or maybe the root=[...] parameter on the kernel command line. For .config, I'd recommend starting with the original .config from 4.3-rc7 and then just running "make oldconfig".
And that helped--in a sense. It produced a kernel that would at least boot partially instead of a kernel panic, but the boot froze on the distro splash screen. It's progress, though! I edited grub.cfg (I've read not to do this, but it was a temporary modification to test a theory) to use "nosplash" instead of "splash" on the kernel command lin grub entry for the kernel I'd compiled, and once I booted that kernal again, I noticied a 'could not locate modules: template usr/lib/modules/$KERNELVERSION" type of error. Again, no way to screenshot it as it was early in the boot process.
I'm guessing now I've discovered the problem: Renaming the /usr/lib/modules/$KERNELVERSION directory to something different than what the "make modules_install" command named it when it built the directory--and prior to running the mkinitcpio command to build the initial ramdisk--is a bad idea. Live and learn.
I'm back on track now, and with any luck and free time between day job and sleep, eventually I'll have a bootable kernel compiled soon so I can actually start bisecting to locate the bad commit.