[SGVLUG] More laptop fun--IRQ assignments

David Lawyer dave at lafn.org
Thu Dec 8 02:30:07 PST 2005


On Tue, Dec 06, 2005 at 05:27:57AM -0800, David Lawyer wrote:
> On Sat, Nov 26, 2005 at 10:58:23PM -0800, Dustin wrote:
> [snip]
> > I'd like to be able to reassign IRQs.  
> [snip]
> 
I just now found this in a hard-to-find HOWTO.  Google's Linux
search engine can't find it.  It's at:

   The   current   version  of  this  document  can  always  be  found  at
   [136]http://www.columbia.edu/~ariel/acpi/acpi_howto.html.  You can also
   find other formats of this document at
   [137]http://www.columbia.edu/~ariel/acpi/.
     __________________________________________________________________
These are args to the kernel command line.  They could be put into
lilo, etc.

   acpi_irq_balance
          ACPI  will  balance active IRQs to minimize sharing. This is the
          default in APIC mode.

   acpi_irq_nobalance
          ACPI   will  not  move  active  IRQs  around  (the  opposite  of
          acpi_irq_balance). This is the default in PIC mode.

   acpi_irq_pci=...
          If  you have set acpi_irq_balance, you have to reserve some IRQs
          for  for  use  by  PCI  or else ACPI may use them all; list them
          here. Format: <irq>,<irq>...

Unfortunately, this HOWTO isn't too strong on the C part of ACPI, but
it's still useful.  I plan to read the C part of it later on.  If you
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.

			David Lawyer


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