Hi Guenter,

On Wed, Jul 22, 2015 at 03:22:57PM +0100, Guenter Roeck wrote:
> On 07/22/2015 02:14 AM, Lorenzo Pieralisi wrote:
> > Bjorn, Guenter,
> >
> > On Thu, Jul 09, 2015 at 11:59:16AM +0100, Lorenzo Pieralisi wrote:
> >> When a PCI bus is scanned, upon PCI bridge detection the kernel
> >> has to read the bridge registers to set-up its resources so that
> >> the PCI resource hierarchy can be validated properly.
> >>
> >> Most if not all architectures read PCI bridge registers in the
> >> pcibios_fixup_bus hook, that is called by the PCI generic layer
> >> whenever a PCI bus is scanned.
> >>
> >> Since pci_read_bridge_bases is an arch agnostic operation (and it
> >> is carried out on all architectures) it can be moved to the generic
> >> PCI layer in order to consolidate code and remove the respective
> >> calls from the architectures back-ends.
> >>
> >> The PCI_PROBE_ONLY flag is not checked before calling
> >> pci_read_bridge_buses in the generic layer since reading the bridge
> >> bases is not related to resources assignment; this implies that it
> >> can be carried out safely on PCI_PROBE_ONLY systems too and should
> >> not affect architectures (alpha, mips) that check the PCI_PROBE_ONLY
> >> flag before reading the bridge bases.
> >>
> >> Signed-off-by: Lorenzo Pieralisi <[email protected]>
> >> Cc: Ralf Baechle <[email protected]>
> >> Cc: James E.J. Bottomley <[email protected]>
> >> Cc: Michael Ellerman <[email protected]>
> >> Cc: Bjorn Helgaas <[email protected]>
> >> Cc: Richard Henderson <[email protected]>
> >> Cc: Benjamin Herrenschmidt <[email protected]>
> >> Cc: David Howells <[email protected]>
> >> Cc: Russell King <[email protected]>
> >> Cc: Tony Luck <[email protected]>
> >> Cc: David S. Miller <[email protected]>
> >> Cc: Ingo Molnar <[email protected]>
> >> Cc: Guenter Roeck <[email protected]>
> >> Cc: Michal Simek <[email protected]>
> >> Cc: Chris Zankel <[email protected]>
> >> ---
> >> v2->v3:
> >>
> >> - Dropped RFC status
> >> - Removed bridge resources claiming from pci_read_bridge_bases()
> >
> > What do you want me to do with this patch ? I removed the resource
> > claiming - ie the only controversial bit, I can only test on
> > arm64, I would like to make some progress on this otherwise
> > I will have to add the bridge bases read to arm64 pcibios_fixup_bus()
> > and be done with this.
> >
> 
> Lorenzo,
> 
> please give me a few days to test it. I was out on vacation for
> the last two weeks, and I am still struggling to get my test systems
> back to a working state.

No worries, I just wanted to make sure we can make progress on this,
I do not think there is anything controversial in this set, it just
requires testing the mechanical change on all affected archs, that's
the problem.

Thanks a lot for your help !
Lorenzo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to