What do these parameters mean?

[Mauvve Knight]

Okay, I am curious (some times too curious?) and during my 'voyage of discovery' I took a look at System Management. My attention was grabbed by header 'Startup Parameters'.

It states:

pcie_ports=native intel_iommu=on iommu=pt quiet splash initrd=boot\initrd.img-6.19.3-1-t2

.. What do they mean?

 

[tinfoil-hat]

IOMMU is a virtualization technology for passing through PCI devices to VMs. Let's say you have 2 graphics cards and want one dedicated to your VM, you can pass it through. Or a sound / LAN Card

 

[MikeRocor]

Code:
pcie_ports=native intel_iommu=on iommu=pt quiet splash initrd=boot\initrd.img-6.19.3-1-t2

"quiet" limits the verbosity of the kernel during boot up.

"initrd=..." tells the boot loader where to find the init ramdisk, which contains a, usually minimal, root file system. many distros use the intrd to do some set up before doing a chroot to the "main" root fs on disk. Other distros just keep the initrd as the root fs.

I'm less clear about what "pcie-ports=..." and "splash" do.

Edit: While the kernel will act on boot codes that it recognizes, it will ignore those that it does not recognize. All of the boot codes are visible after boot up in /proc/cmdline, so you can use custom boot codes to provide various bits of info that can then be read by scripts or applications as needed. This can be useful, for instance, when setting up a bootable USB stick that might be used on a variety of different machines with different capabilities or in different environments.

 

[Alexzee]

The pcie ports paramater is used to configure how the os handels pci express services like hotplug and advanced error reporting. Splash passed to the kernel shows a graphical boot splash screen.

 

[wizardfromoz]

Having "no quiet no splash" in my /etc/default/grub means that instead of having the graphical screen with a progress indicator of dots/ellipses going around or changing colour, I get a spooling page or several of indicators as to what is happening on the way to the desktop, and allows me to troubleshoot any warnings ore errors that may need attention.

The more RAM you have (I have 16GB), the faster that output spools off, so I may have to check logs later to define problems.

HTH

Wiz