Re: libata, devm_*, and MSI ?

[Mark Lord]

Grant Grundler wrote:
> On Tue, Jan 20, 2009 at 8:03 AM, Mark Lord <liml@xxxxxx> wrote:
..
> > For starters, the MSI HOW-TO suggests that drivers must be careful
> > to invoke pci_disable_msi() on module unload, but I don't see that
> > happening anywhere in libata.
>
> I don't think that's necessary if free_irq() or disable_irq() are called.
> However, I'm not seeing those get called either.
..

The linux/Documentation/PCI/MSI-HOWTO.txt information is rather explicit
about it, and the pci core code does seem to expect it.

> However, I'm not seeing those get called either.
..

The devres code takes care of the free_irq() normally,
but does not do the pci_disable_msi(), because it doesn't
know enough about the device to do it right now.

..
> > Eg. from ahci.c, we have this:
> >
> >       if ((hpriv->flags & AHCI_HFLAG_NO_MSI) || pci_enable_msi(pdev))
> >               pci_intx(pdev, 1);
> >
> > Which agrees with the existing code in sata_mv:
> >
> >       if (msi && hi jiqi(pdev))
> >               pci_intx(pdev, 1);
..
> >       if (pci_enable_msi(pdev) == 0)
> >               pci_intx(pdev, 0);
> >
> > Either that one is wrong, or pci_intx() is unnecessary in all cases.
..

Those calls to pci_intx() are definitely redundant,
as the pci core already does that for us on the relevant paths.

> > Perhaps somebody from the PCI side of things might enlighten us all.
>
>     http://lists.linuxcoding.com/kernel/2005-q3/msg11296.html
>
> Shows when pci_intx() was added. linux-pci was NOT cc'd on that email.
> And no one asked for Documentation/ update. C'est la vie.
..

I still think the documentation matches the code in the pci core, though.

Patch for sata_mv coming shortly.

Cheers
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/