我回滚了 wacom 驱动程序并重新安装了 Nvidia 驱动程序，但现在kdm无法启动。
> systemctl status kdm
kdm[3954]: plymouth is running
kdm[3954]: plymouth is active on VT 1, reusing for :0
kdm[3954]: plymouth should quit after server startup
kdm[3967]: X server "/bin/X" cannot be executed
kdm[3954]: X server for display :0 cannot be started, session disabled
kdm[3954]: Quitting Plymouth without transition
kdm[3954]: plymouth is NOT running
检查nvidia-smi：
> nvidia-smi
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 390.25 Driver Version: 390.25 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
|===============================+======================+======================|
| 0 TITAN Xp COLLEC... Off | 00000000:17:00.0 Off | N/A |
| 23% 38C P0 61W / 250W | 0MiB / 12196MiB | 0% Default |
+-------------------------------+----------------------+----------------------+
| 1 TITAN Xp Off | 00000000:65:00.0 Off | N/A |
| 26% 45C P0 60W / 250W | 0MiB / 12192MiB | 0% Default |
+-------------------------------+----------------------+----------------------+
+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name Usage |
|=============================================================================|
| No running processes found |
+-----------------------------------------------------------------------------+
退房grub
> cat /etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="powernow-k8.disable=1 intel_pstate=disable selinux=0 crashkernel=auto rd.lvm.lv=centos_vxfhost/root rd.lvm.lv=centos_vxfhost/swap nomodeset net.ifnames=0 rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
诊断并使其再次运转的最佳方法是什么？