RE: Spurious interrupt warning

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Hi,

> * Hiremath, Vaibhav <hvaibhav@xxxxxx> [090106 13:13]:
> > For capture driver I am also getting similar messages
> >
> > <4>Spurious irq 95: 0xffffffdf, please flush posted write for irq 24
> > Spurious irq 95: 0xffffffdf, please flush posted write for irq 24
> > <4>Spurious irq 95: 0xffffffdf, please flush posted write for irq 24
> > Spurious irq 95: 0xffffffdf, please flush posted write for irq 24
>
> The same solution should work in the irq 24 handler as well. Just do
> a read-back of the last written register in the irq 24 handler.
>
> Or a read back of some safe register in the same device in case
> you cannot read back the interrupt status register without clearing
> the device interrupts :)

I'll re-raise the opinion that SO should be used for device mappings on OMAP.

This is not just an IRQ issue.  It's a generic one to programming a device and knowing when what you have written has taken.

It just happens to be the IRQ path has a very slow dissertation path when you take into account timing domains that it shows up.

Shrinking the race window with SO then using a read back to get the last one or two is most conservative and safe.  Probably 97% for IO accesses are ok on OMAP as device, but that is probably 99.9% with SO.  In our testing we may be able to make that 97 a 99.  Still I'd rather not risk the 1% for production.

Regards,
Richard W.

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