Re: [RFC PATCH] PCI: remove access to pci_[enable|disable]_msi() for drivers

Arjan van de Ven
2005-06-07T20:41:44Z

On Tue, 2005-06-07 at 09:10 -0700, Greg KH wrote:
> On Tue, Jun 07, 2005 at 09:31:39AM +0200, Arjan van de Ven wrote:
> >
> > > > * What if the driver writer does not want MSI enabled for their
> > > > hardware (even though there is an MSI capabilities entry)? Reasons
> > > > include: overhead involved in initiating the MSI; no support in some
> > > > versions of firmware (QLogic hardware).
> > >
> > > Yes, a very good point. I guess I should keep the pci_enable_msi() and
> > > pci_disable_msi() functions exported for this reason.
> > >
> >
> > well... only pci_disable_msi() is needed for this ;)
>
> I thought so too, until I looked at the IB driver :(
>
> The issue is, if pci_enable_msix() fails, we want to fall back to MSI,
> so you need to call pci_enable_msi() for that (after calling
> pci_disable_msi() before calling pci_enable_msix(), what a mess...)

if the core enables msi.. shouldn't the core also do msix ?