On Fri, Sep 28, 2012 at 12:07:31AM -0400, Brad Smith wrote:
> On Fri, Sep 28, 2012 at 04:06:32AM +0200, Mark Kettenis wrote:
> > > Date: Mon, 24 Sep 2012 03:49:41 -0400
> > > From: Brad Smith <b...@comstyle.com>
> > >
> > > I've always wondered why this workaround was not removed once MSI
> > > support was added. This was added before we had MSI support to
> > > workaround some Intel azalia(4) being setup by the BIOS as far
> > > as I know to use MSI and thus interrupts on system that were
> > > affected by this did not work at all for azalia(4).
> >
> > Because there still are conditions under which we would not be able to
> > use MSI.
>
> I had 6 people reply off list indicating their Intel azalia controllers
> didn't seem to have any regressions with the previous diff applied.
>
> Can you expand upon this and explain what you mean. What are these
> conditions? It would be nice to mention what those conditions are
> within the comment.
>
> > Perhaps we should change the generic PCI code to explicitly disable
> > MSIs if they are turned on. But until we do that, this workaround
> > needs to stay in place.
>
> Since MSI is being disabled for the Intel azalia controller and the
> datasheet does confirm that is what this code is doing shouldn't
> we be telling the PCI layer MSI is disabled too like so? It doesn't
> make sense to have MSI disabled for the controller and then the
> PCI layer still thinking MSI should be used.
ping.
> Index: azalia.c
> ===================================================================
> RCS file: /home/cvs/src/sys/dev/pci/azalia.c,v
> retrieving revision 1.201
> diff -u -p -r1.201 azalia.c
> --- azalia.c 12 Aug 2012 19:32:22 -0000 1.201
> +++ azalia.c 28 Sep 2012 02:17:31 -0000
> @@ -515,6 +515,7 @@ azalia_pci_attach(struct device *parent,
>
> /* disable MSI, use INTx instead */
> if (PCI_VENDOR(sc->pciid) == PCI_VENDOR_INTEL) {
> + pa->pa_flags &= ~PCI_FLAGS_MSI_ENABLED;
> reg = azalia_pci_read(sc->pc, sc->tag, ICH_PCI_MMC);
> reg &= ~(ICH_PCI_MMC_ME);
> azalia_pci_write(sc->pc, sc->tag, ICH_PCI_MMC, reg);
--
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