我刚刚从 18.04 升级到 20.04 (LTS)。但现在我无法播放全屏视频，无论是通过网络浏览器还是 VLC。每当我选择全屏视频时。它会在左上角产生“画中画”效果，如下图所示。
https://i.stack.imgur.com/kKaWq.jpg
我的机器是 win10 双启动，Acre Aspire 5。输出sudo lshw -C video是
*-display
description: VGA compatible controller
product: Intel Corporation
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
logical name: /dev/fb0
version: 07
width: 64 bits
clock: 33MHz
capabilities: pciexpress msi pm vga_controller bus_master cap_list rom fb
configuration: depth=32 driver=i915 latency=0 mode=1920x1080 visual=truecolor xres=1920 yres=1080
resources: iomemory:600-5ff iomemory:400-3ff irq:131 memory:6012000000-6012ffffff memory:4000000000-400fffffff ioport:6000(size=64) memory:c0000-dffff
*-display UNCLAIMED
description: 3D controller
product: GP107M [GeForce MX350]
vendor: NVIDIA Corporation
physical id: 0
bus info: pci@0000:02:00.0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list
configuration: latency=0
resources: iomemory:600-5ff iomemory:600-5ff memory:50000000-50ffffff memory:6000000000-600fffffff memory:6010000000-6011ffffff ioport:5000(size=128)
已安装 Ubuntu 驱动程序 https://i.stack.imgur.com/MTXxx.png
更新 1
18.04 到 20.04 更新中似乎存在一个错误，它“阻止”某些关键驱动程序/软件的安装。
1.）用来ubuntu-drivers devices找出缺少哪个驱动程序并且（推荐）......
2.）然后使用sudo ubuntu-drivers autoinstall
实际上失败了...出现以下错误：
Setting up linux-modules-nvidia-450-5.4.0-48-generic (5.4.0-48.52) ...
debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable
dpkg: error processing package linux-modules-nvidia-450-5.4.0-48-generic (--configure):
installed linux-modules-nvidia-450-5.4.0-48-generic package post-installation script subprocess returned error exit status 1
Setting up libnvidia-cfg1-450:amd64 (450.66-0ubuntu0.20.04.1) ...
Setting up screen-resolution-extra (0.18build1) ...
Setting up libnvidia-extra-450:amd64 (450.66-0ubuntu0.20.04.1) ...
Setting up nvidia-settings (440.82-0ubuntu0.20.04.1) ...
Setting up libnvidia-decode-450:amd64 (450.66-0ubuntu0.20.04.1) ...
Setting up libnvidia-decode-450:i386 (450.66-0ubuntu0.20.04.1) ...
Setting up libnvidia-fbc1-450:amd64 (450.66-0ubuntu0.20.04.1) ...
Setting up libnvidia-fbc1-450:i386 (450.66-0ubuntu0.20.04.1) ...
Setting up xserver-xorg-video-nvidia-450 (450.66-0ubuntu0.20.04.1) ...
Setting up nvidia-kernel-common-450 (450.66-0ubuntu0.20.04.1) ...
update-initramfs: deferring update (trigger activated)
Setting up libnvidia-gl-450:amd64 (450.66-0ubuntu0.20.04.1) ...
Setting up libnvidia-gl-450:i386 (450.66-0ubuntu0.20.04.1) ...
Setting up libnvidia-encode-450:amd64 (450.66-0ubuntu0.20.04.1) ...
Setting up libnvidia-encode-450:i386 (450.66-0ubuntu0.20.04.1) ...
dpkg: dependency problems prevent configuration of linux-modules-nvidia-450-generic-hwe-20.04:
linux-modules-nvidia-450-generic-hwe-20.04 depends on linux-modules-nvidia-450-5.4.0-48-generic (= 5.4.0-48.52); however:
Package linux-modules-nvidia-450-5.4.0-48-generic is not configured yet.
dpkg: error processing package linux-modules-nvidia-450-generic-hwe-20.04 (--configure):
dependency problems - leaving unconfigured
Setting up libnvidia-ifr1-450:amd64 (450.66-0ubuntu0.20.04.1) ...
No apport report written because the error message indicates its a followup error from a previous failure.
Setting up libnvidia-ifr1-450:i386 (450.66-0ubuntu0.20.04.1) ...
dpkg: dependency problems prevent configuration of nvidia-driver-450:
nvidia-driver-450 depends on nvidia-dkms-450 (<= 450.66-1); however:
Package nvidia-dkms-450 is not installed.
Package linux-modules-nvidia-450-generic-hwe-20.04 which provides nvidia-dkms-450 is not configured yet.
nvidia-driver-450 depends on nvidia-dkms-450 (>= 450.66); however:
Package nvidia-dkms-450 is not installed.
Package linux-modules-nvidia-450-generic-hwe-20.04 which provides nvidia-dkms-450 is not configured yet.
dpkg: error processing package nvidia-driver-450 (--configure):
dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
Processing triggers for mime-support (3.64ubuntu1) ...
Processing triggers for gnome-menus (3.36.0-1ubuntu1) ...
Processing triggers for libc-bin (2.31-0ubuntu9.1) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for desktop-file-utils (0.24-1ubuntu3) ...
Processing triggers for initramfs-tools (0.136ubuntu6.3) ...
update-initramfs: Generating /boot/initrd.img-5.4.0-48-generic
I: The initramfs will attempt to resume from /dev/nvme0n1p6
I: (UUID=5fc4b948-a7d5-454c-a0d8-7160f260d09f)
I: Set the RESUME variable to override this.
Errors were encountered while processing:
linux-modules-nvidia-450-5.4.0-48-generic
linux-modules-nvidia-450-generic-hwe-20.04
nvidia-driver-450
E: Sub-process /usr/bin/dpkg returned an error code (1)
然而，我能够使用与无法安装快门的问题相同的解决方案立即修复它。
答案是在这篇文章中
完成此操作后，我就能完成正确的 nvidia 驱动程序的安装，重新启动，并验证它已安装在“软件和更新”中......
经过这一切……同样的问题……这绝对是 Ubuntu 20.04 的一个错误……这台机器上安装了 18.04……没有问题。结果sudo lshw -C video仍然是display: UNKNOWN
更新 2
我回去尝试了下面列出的 @hyttysmyrkky 建议的所有解决方案。但都不起作用。结果sudo lshw -C video总是display: UNKNOWN。仅供参考，这包括使用 -47 内核和 440.100 驱动程序。所有解决方案都不起作用，同样的画中画、全屏模式问题。除了这个错误之外，在 20.04 下我还遇到了以下问题：
1.) 无法通过系统菜单关闭我的机器。屏幕变暗，但无论我等待多久，关机过程都会挂起，最后需要按住电源按钮才能硬关机。
2.) 启动时，我的英特尔 wifi 卡识别时好时坏。如果失败，我需要重新启动才能使 wifi 正常工作，因为重新启动网络管理器没有任何效果
3.) 非常恼人地频繁，在启动时我会收到 MOK 消息（机器所有者密钥），要求我在 grub 之前选择启动系统。无论我之前做过多少次同样的事情，这种情况都会发生。
4.) 通常，BIOS 设置会恢复为系统默认值，完全绕过 grub 并加载 win10，因此需要：1.) 在安全模式下重新启动 Windows，2.) 进入 BIOS 将“sata 设置”从“带阵列的 RAID”更改为“AHCI”，禁用快速启动，3) 重新登录 Win10 关闭安全模式并重新启动。（即浪费大量时间）
我终于“解决”了这个问题，方法是恢复到 18.04，其中“手动安装驱动程序”选项似乎与 nvidia 驱动程序完美配合。20.04 很“养眼”，但我要等一年才会再次尝试升级。刚刚切换到 18.04 上的 NVIDIA-driver-450-server，它也运行完美。
答案1
如果您已成功安装 nvidia-driver-450，这可能与之无关，但我还是会告诉您：Ubuntu 20 的最新内核更新（从 5.4.0-47 到 5.4.0-48）似乎与 Nvidia 驱动程序存在一些问题：
- NVIDIA 驱动程序突然失效（20.04 LTS）（这里可能有解决办法）
这里也报告了该问题：
- https://stackoverflow.com/questions/64076302/problems-when-starting-ubuntu-20-04-on-the-kernel-5-4-0-48-generic
- https://forums.developer.nvidia.com/t/nvidia-driver-no-longer-loading-on-ubuntu-20-04/155128
nvidia-smi（我现在必须切换回内核 5.4.0-47 和 Nvidia 驱动程序 440.100（据报道，因为 Ubuntu 没有显示版本，但出于某种原因只显示“手动安装的驱动程序”）。）