I have a ThinPad T430 ( http://www.thinkwiki.org/wiki/Category:T430 ), which I use in pure UEFI mode.
About the system:
It has NVIDIA NVS 5400M GPU, which is set to native mode, so Optimus is not enabled in the UEFI firmware setup. It also has an integrated Intel GPU, that is disabled from UEFI. (You can only choose either the Intel or the NVidia one, or to enable Optimus.)
I have installed Slackware64 14.2 and updated the system with the most recent packages.
All seems okay and working with the 4.4.74 distribution kernel. (It uses the nouveau driver.)
I use LVM, therefore I have to use an (xz compressed) initrd. How it has to be used was described to be by AlienBob ( http://www.linuxquestions.org/questions/slackware-installation-40/booting-with-xz-compressed-initrd-4175599273/ )
The problem is, that with the kernel (4.9.34) I configured, there is no graphics output during the boot process. The display is only initialized when X starts, and even then, there is nothing displayed when switching back to the text console. (The console actually works even though nothing is displayed.)
I disabled the nouveau, and nvidiafb drivers, because I installed the proprietary NVidia driver (375.66). I put the driver into the initrd (nvidia.ko, nvidia-drm.ko, nvidia-kms.ko), because I have to use an initrd due to the LVM I use.
I would like to be able to use a high resolution text console, and also use X.
I have also left the intel vga driver compiled in, so that in case I change my mind, I won’t need to recompile my kernel.
The high resolution console works fine with the intel driver, and even with nouveau.
What may I be missing?
I can provide the kernel configuration and dmesg output if that helps.
The original LinuxQuestions thread can be found here: http://www.linuxquestions.org/questions/slackware-14/building-my-own-kernel-no-video-output-on-notebook-lcd-4175608827/