当我在 16.04 上运行内核或 NVIDIA 驱动程序更新时，这会触发 initramfs 重建并输出以下警告：
Processing triggers for initramfs-tools (0.122ubuntu8.1) ...
update-initramfs: Generating /boot/initrd.img-4.4.0-34-generic
W: Possible missing firmware /lib/firmware/i915/skl_guc_ver6.bin for module i915_bpo
我有一个带有两个图形芯片的笔记本电脑，一个 NVIDIA GeForce 940M 和一个 Intel i5-6200U 的集成显卡。
使用的设备是我的 NVIDIA 卡：
$ inxi -G
Graphics: Card-1: Intel Sky Lake Integrated Graphics
Card-2: NVIDIA GM108M [GeForce 940M]
Display Server: X.Org 1.18.3 driver: nvidia Resolution: 1920x1080@60.03hz
GLX Renderer: GeForce 940M/PCIe/SSE2 GLX Version: 4.5.0 NVIDIA 367.35
这是lshw -c video，对应于应该使用该驱动程序的英特尔图形芯片的输出：
*-display
description: VGA compatible controller
product: Sky Lake …我该如何解决这个警告？
addgroup: The group `input' already exists as a system group. Exiting.
update-initramfs: deferring update (trigger activated)
Setting up grub-common (2.02~beta2-36ubuntu3.21) ...
update-rc.d: warning: start and stop actions are no longer supported; falling back to defaults
Setting up grub2-common (2.02~beta2-36ubuntu3.21) ...
Setting up grub-efi-amd64-bin (2.02~beta2-36ubuntu3.21) ...
Setting up grub-efi-amd64 (2.02~beta2-36ubuntu3.21) ...
Installing for x86_64-efi platform.
Installation finished. No error reported.
Generating grub configuration file ...
Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported. …