It may appear to be an Xorg or lightdm/gdm/mdm error but in reality for many users with this issue, it's a driver conflict and issue. I had a system that had two GPUs, an Intel and Nvidia GPU.
The only thing that got it working was to remove the nouveau driver and blacklist it so it never came back, then the Intel GPU works fine without these issues.
Solution
sudo rmmod nouveau
add nouveau/other driver to blacklist
edit th........
This is the reason that I don't like the new ADATA USB drives such as the UV128/64GB or 128GB drives and other ones that look to be the same style (the green sliding USB connector).
They just don't work well from new and never work properly at any point.
[ 788.242463] usb 1-1.2: new high-speed USB device number 16 using ehci-pci
[ 788.339816] usb 1-1.2: New USB device found, idVendor=125f, idProduct=db8a
[ 7........
I tried to stop a qemu-img copy or clone and it broke everything. It was fine to "stop" it from the GUI but a process still persisted so I killed the relevant qemu-img and the kernel went crazy. It also may not have helped that I tried to lvremove a different volume (an unused disk). But either way it breaks LVM (you cannot even run lvdisplay) so a reboot is necessary.
Jan 17 06:45:21 testserver kernel: [ 5680.439337] systemd-udevd D 0&nbs........
systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system.
The key commands or arguments you will use with systemctl are the following:
Unit Commands:
list-units [PATTERN...] List loaded units
&nbs........
At first my BIOS said the card may not work right because there is no more option ROM space.
I disabled the Option ROM for both LSI 1068 and 2008 chipsets, Network Boot ROM and most other PCI slots, Serial Port, etc... and the message went away but the card still does not work properly.
But it still cannot initialize the card properly(does not work):
[ 33.943272] NVRM: This PCI I/O region assigned to your NVIDIA device is invalid:........
If you move your hard drive(s) around to other computers/servers, you'll find that your eth0 keeps getting higher, the first time it will become eth1 and then eth2 etc and even higher if your server has dual or quad NICs. The reason is that udevd basically assigns eth0 tot he first NIC it finds and remembers it, if it encounters a NIC with a differentMAC, it assigns it one higher (eg. eth1).
See the example below, I have eth2 now so how doI fix it?........