Messages in this thread | | | From | Bjorn Helgaas <> | Date | Fri, 4 Oct 2013 11:36:33 -0600 | Subject | Re: [PATCH] x86: fix PCI_MSI build on !SMP |
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[+cc Konrad]
On Thu, Oct 3, 2013 at 3:59 AM, Thomas Petazzoni <thomas.petazzoni@free-electrons.com> wrote: > Commit ebd97be635 ('PCI: remove ARCH_SUPPORTS_MSI kconfig option') > removed the ARCH_SUPPORTS_MSI option which architectures could select > to indicate that they support MSI. Now, all architectures are supposed > to build fine when MSI support is enabled: instead of having the > architecture tell *when* MSI support can be used, it's up to the > architecture code to ensure that MSI support can be enabled. > > On x86, commit ebd97be635 removed the following line: > > select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC) > > Which meant that MSI support was only available when the local APIC > and I/O APIC were enabled. While this is always true on SMP or x86-64, > it is not necessarily the case on i386 !SMP. > > The below patch makes sure that the local APIC and I/O APIC support is > always enabled when MSI support is enabled. To do so, it: > > * Ensures the X86_UP_APIC option is not visible when PCI_MSI is > enabled. This is the option that allows, on UP machines, to enable > or not the APIC support. It is already not visible on SMP systems, > or x86-64 systems, for example. We're simply also making it > invisible on i386 MSI systems. > > * Ensures that the X86_LOCAL_APIC and X86_IO_APIC options are 'y' > when PCI_MSI is enabled. > > Notice that this change requires a change in drivers/iommu/Kconfig to > avoid a recursive Kconfig dependencey. The AMD_IOMMU option selects > PCI_MSI, but was depending on X86_IO_APIC. This dependency is no > longer needed: as soon as PCI_MSI is selected, the presence of > X86_IO_APIC is guaranteed. Moreover, the AMD_IOMMU already depended on > X86_64, which already guaranteed that X86_IO_APIC was enabled, so this > dependency was anyway redundant. > > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> > Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Cc: bhelgaas@google.com > Cc: benh@kernel.crashing.org > Cc: daniel.price@gmail.com > Cc: thierry.reding@gmail.com > Cc: linux-kernel@vger.kernel.org > Cc: jason@lakedaemon.net > Cc: x86@kernel.org
FWIW,
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
x86 maintainers, I assume you'll pick this up. Let me know if you want me to do it.
Bjorn
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