Re: Possible issue with dangling PCI BARs

[Jesse Barnes <jesse.barnes@intel.com>]

On Thursday, December 13, 2007 3:20 Benjamin Herrenschmidt wrote:
> > > Supporting pci_enable_device_io / pci_enable_device_mmio /
> > > pci_iomap_io / pci_iomap_mmio seems to cover pretty much all the
> > > use cases we have.
> > >
> > > The users we have right now that are:
> > >
> > >         - pata_cs5520   (can be dealt with easily)
> > >         - old IDE       (with the new resource handling for
> > > legacy IDE can use pci_enable_device_io I think, ditto
> > > pci/cs5520)
> > >         - scx200_acb    (looks like a simple substitution works)
> > >         - lpfc          pci_enable_device_mmio
> > >         - qla2xxx       pci_enable_device ? (enables IO and MMIO)
>
> I may have not fully undestood you in my previous reply. You are
> proposing replacing pci_enable_device_bars() with a pair of
> pci_enable_device_io/mem ?
>
> I think that would be a good idea indeed.

Yeah, that seems like a reasonable compromise.  Though in practice I'd 
expect the full disable decode approach to work fairly well too.  I 
mean, if we really end up failing to allocate space for the device with 
the root drive on it, there are probably bigger issues than just 
failing to get a few bytes of I/O space for it...

OTOH like Robert said, many devices really only need either MMIO or IO 
space enabled, not both, so having separate enable/disable routines for 
them makes a lot of sense.

Jesse