[PATCH v2 2/2] powerpc/PCI: Disable MSI/MSI-X interrupts at PCI probe time in OF case
Guilherme G. Piccoli
gpiccoli at linux.vnet.ibm.com
Sat Sep 5 09:17:12 AEST 2015
> of_create_pci_dev() already has a lot of code that duplicates
> pci_setup_device(), and it's a shame to add more. There's also a sparc
> version of of_create_pci_dev() that presumably has the same problem you're
> fixing for powerpc.
Thanks for the information!
> Michael originally called pci_msi_setup_pci_dev() from
> pci_init_capabilities() . A subsequent patch moved the call
> to pci_setup_device()  because an early quirk (called from
> pci_setup_device()) used pci_msi_off(), which depended on
> But we later removed pci_msi_off() completely, so I think we probably
> *could* call pci_msi_setup_pci_dev() from pci_init_capabilities().
> That would be much nicer because it makes more sense there, and it
> would do the right thing for powerpc and sparc because they both
> already use that path.
> Can you look into moving the call?
I might have misunderstood something here (sorry if it's the case), but
moving the call to pci_init_capabilities() has the same practical
implications than reverting my 2 commmits   and Michael Tsirkin's
commit , except when CONFIG_PCI_MSI is not set - in this case, moving
the call would initialize MSI capabilities anyway, since
pci_init_capabilities() executes even if CONFIG_PCI_MSI isn't set.
My question is: is necessary to initialize MSI capabilities even with
CONFIG_PCI_MSI not set? In negative case, would be "cleaner" revert the
3 commits, right?
On the other hand, if it's necessary to initialize MSI capabilities on
devices anyway, we can change the call place.
Let me know your opinion, and I'm sorry if I misunderstood something here.
 commit 22b6839b914b ("PCI: Make pci_msi_setup_pci_dev() non-static
for use by arch code")
 commit 4d9aac397a5d ("powerpc/PCI: Disable MSI/MSI-X interrupts at
PCI probe time in OF case")
 commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if
kernel doesn't support MSI")
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