我无法添加所需的存储库来安装nvidia-graphics-drivers-319。我不明白为什么密钥不受信任。查看所需命令的输出：
root@barry-III:/home/zombie# add-apt-repository ppa:ubuntu-x-swat/x-updates
Updated versions of X.org drivers, libraries, etc. for Ubuntu.
This PPA is for stable upstream releases of X.org components. If you're looking for something even more bleeding-edge, please see the xorg-edgers PPA.
While Ubuntu does not "officially/formally" support these packages, if you discover problems when installing these debs please feel free to report bugs to launchpad. However, please make sure to clearly state that you are running packages from this PPA so we know the fixes need to come here.
If you are upgrading from one release to another with this PPA activated, please install the ppa-purge package and use it to downgrade everything in here beforehand. sudo ppa-purge ppa:ubuntu-x-swat/x-updates will do it.
[Directions for packaging drivers can be seen at https://wiki.ubuntu.com/X/DriverBuilding]
More info: https://launchpad.net/~ubuntu-x-swat/+archive/x-updates
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keyring `/tmp/tmph015_y/secring.gpg' created
gpg: keyring `/tmp/tmph015_y/pubring.gpg' created
gpg: requesting key AF1CDFA9 from hkp server keyserver.ubuntu.com
gpg: /tmp/tmph015_y/trustdb.gpg: trustdb created
gpg: key AF1CDFA9: public key "Launchpad PPA for Ubuntu-X" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
OK
root@barry-III:/home/zombie# apt-get install nvidia-graphics-drivers-319
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package nvidia-graphics-drivers-319
root@barry-III:/home/zombie#
答案1
事实并非如此nvidia-graphics-drivers-319，nvidia-319因此运行以下命令，
sudo apt-get update
sudo apt-get install nvidia-319
答案2
添加 PPA 运行后：
sudo apt-get update
重新加载软件包列表并重试。确保 PPA 包含您当前正在使用的 ubuntu 版本的软件包。