Re: [patch] PCI: disable MSI on more ATI NorthBridges

[Jeff Garzik]

Linas Vepstas wrote:
> On Fri, Oct 19, 2007 at 09:17:23PM +0800, Shane Huang wrote:
> > Since we have little experience on PCI and MSI here, we had to try to
>
> As someone else pointed out, AMD should have *lots* of people with
> pci and msi experience on the payroll.  (Folks here buy AMD-designed 
> pci chips ...)
>
> > ONLY
> > comment out the pci_intx() call in drivers/ata/ahci.c
> > My system can boot up too with MSI enabled!
> >
> > So does it mean that the root cause is our SB700 SATA controller
> > has a hardware bug where setting INTX_DISABLE in the PCI COMMAND
> > register masks MSI interrupts too? 
>
> That's what it sounds like, to me.
>
> > And what is the software solution or workaround?
>
> Not sure. Sounds like the device driver needs a quirk for this part.


Take a look at tg3.c net driver change 
2fbe43f6f631dd7ce19fb1499d6164a5bdb34568 which is a similar situation.

However, it may turn out that removing the pci_intx() stuff as a general 
rule is easier than quirking these devices, if enough of them turn out 
to have this hardware bug.

The tg3.c change should illustrate how to fix immediately, though.

	Jeff

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