Re: [PATCH] Fix incorrect Asus k7m irq router detection

[Dave Jones <davej@redhat.com>]

On Wed, Jul 27, 2005 at 10:16:30AM +0200, Giancarlo Formicuccia wrote:

 > this patch:
 > http://marc.theaimsgroup.com/?l=bk-commits-head&m=111955644929114&w=2
 > uncovered a k7m bios bug, where the VT82C686A router is reported as
 > being "586-compatible". The two chips have different pirq mapping, so
 > this leads to "irq routing conflict" on many pci devices.
 > 
 > The suggested fix was discussed with Aleksey Gorelov, who helped me
 > to identify the problem as a probable bios bug.
 > 
 > Patch for 2.6.13-git4.
 > 
 > Signed-off-by: Giancarlo Formicuccia <giancarlo.formicuccia@gmail.com>
 > 
 > --- linux-2.6.13-rc3-git4/arch/i386/pci/irq.c.org	2005-07-27 08:58:05.000000000 +0200
 > +++ linux-2.6.13-rc3-git4/arch/i386/pci/irq.c	2005-07-27 08:59:29.000000000 +0200
 > @@ -550,6 +550,13 @@
 >  static __init int via_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
 >  {
 >  	/* FIXME: We should move some of the quirk fixup stuff here */
 > +
 > +	if (router->device == PCI_DEVICE_ID_VIA_82C686 &&
 > +			device == PCI_DEVICE_ID_VIA_82C586_0) {
 > +		/* Asus k7m bios wrongly reports 82C686A as 586-compatible */
 > +		device = PCI_DEVICE_ID_VIA_82C686;
 > +	}
 > +
 >  	switch(device)
 >  	{
 >  		case PCI_DEVICE_ID_VIA_82C586_0:

If this really is a problem with that board, it should have a DMI entry
for that board alone, not for every VIA chipset that uses the 586/686 combo,
as I'm fairly certain there are some that legitimately use this combination,
and the patch above will force them all to be reported as 82C686's.

		Dave