PCI=NOMSI , what is it and why we need to add it ?

[OssNass]

Hello
I'm new to this forum and I've been thinking this is the best place to ask about this extra command to the Linux kernel's command line .
My laptop is ASUS X61SL with Intel Core2Duo P8400 Processor and F50L motherboard.
In order to boot I have to add pci=nomsi or acpi=off to the kernel's command line.
I have a small idea about MSI, but I wish to learn more and more importantly I wish to learn why I have to add it .

 

[ryanvade]

Well, acpi=off is basically turning off acpi. To learn about ACPI:
http://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface
I particularly like this line:

Linus Torvalds, creator of the Linux kernel, once described it as "a complete design disaster in every way" in relation to his view that "modern PCs are horrible". Some software developers have trouble implementing ACPI, and express concerns about the requirements that bytecode from an external source must be run by the system with full privileges.

Then, pci=nomsi just disables nomsi
http://www.nvnews.net/vbulletin/showthread.php?t=120710
http://en.wikipedia.org/wiki/Message_Signaled_Interrupts
Is that what you are looking for?

 

[OssNass]

That answers the question of what but not the question of why.
As I recall this problem started with Ubuntu 9 or 10
Can I say that my laptop doesn't implement MSI in it's hardware ?!
Seems kind of odd considering that my laptop is 5 years old