[SGVLUG] More laptop fun--IRQ assignments

[David Lawyer]

On Thu, Dec 08, 2005 at 06:53:23PM -0800, Mike Fedyk wrote:
> Dustin wrote:
> >On Thu, 8 Dec 2005, David Lawyer wrote:
> >  
> >>tell it to balance and it doesn't, there's either a bug in the sw or
> >>the hardware doesn't have enough pci interrupt traces.
> >>    
> >
> >The latter is what I'm afraid of.
> Let's pray for bugs in Linux then.

A bug in the sw is not necessarily in Linux.  It could be in the ACPI
code provided by the BIOS and executed by Linux using an interpreter
provided by Intel.  The ACPI code is to be run on the CPU by Linux,
but the code is in a special ACPI language which needs to be
interpreted.  It's called AML = ACPI Machine Language which is
complied from ACPI Source Language (ASL).  AML is like compressed ASL.
Linux has to use the provided ACPI code to set up the routing table
for the APIC (Interrupt Controller).  I know machine language normally
isn't interpreted but the interpreter may disassemble it first back to
ASL before interpreting.

Wasn't it nice of Intel to provide Linux with their interpretor.  I
don't think MS is that cooperative.  And speaking of MS, people using
Windows are also having the same problem of all devices assigned one IRQ.
And from a Window's discussion about it that I looked at, the
participants didn't seem to have a clue as to why it was happening.

			David Lawyer