kexec(8) needs to get the framebuffer address in order to set up the
new kernel's boot parameters. This is one of the reasons that using a
>4.20 kernel in Heads prevents framebuffer graphics from working in the
OS kernel.
Linux 4.20 started hiding this address from userspace, because
userspace is not supposed to need physical memory addresses. A
workaround was added to keep leaking the address, apparently for some
proprietary userspace OpenGL drivers. This requires both a Kconfig and
a kernel parameter.
This commit enables the Kconfig on the librem_common config, and the
kernel parameter on the librem_15v4 (where I'm testing this). We will
need to enable it on other >4.20 configs/boards as well.
Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>
abbc1b5dd8