Re: msi_free_irqs #2

On Thu, 24 May 2007 11:07:56 -0500
"Mike Miller (OS Dev)" <mikem@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

So I guess I found the answer to my own question. msi_free_irqs was apparently added
in 2.6.22-something. I don't find it in 2.6.21.2 or anywhere else. So somebody broke a
couple of things.
The most noticable is cciss hangs after turning on interrupts. The reason for that is
the kernel now looks at my array of MSI-X vectors in reverse order. We have 4 ways of
generating an interrupt on Smart Array hw. They are:

# define DOORBELL_INT 0
# define PERF_MODE_INT 1
# define SIMPLE_MODE_INT 2
# define MEMQ_MODE_INT 3

For INTx these four lines are OR'ed together and run to one interrupt pin. MSI-X
breaks this hardware OR'ing so we must register either all 4 or at the least the
correct interrupt. When I first submitted the MSI/X support I was registering all 4.
Someone changed that to only register a single MSI-X vector. That worked fine until
2.6.22-something.
Now it appears that the kernel is looking at the array in reverse order. IOW, I must
register PERF_MODE_INT in order for cciss to work. That's messed up. Anybody want to
`fess up to making these changes? :)
I'll keep working this, but I'm going to undo someones change when I figure out where
it's broke.


I'd guess that you're referring to Michael's changes. If you can identify
the offending code in a less vague fashion, more confident answers can
be given ;)

I canot find any sign of anyone altering the IRQ handling in cciss.c after
your initial MSI-support merge. But that's perhaps isn't what you meant.
it's all rather foggy. Please either quote file-n-line, or grab a copy
of git-blame.
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