(2013/06/12 13:45), Bjorn Helgaas wrote: > [+cc Vivek, Haren; sorry I didn't think to add you earlier] > > On Tue, Jun 11, 2013 at 12:08 AM, Takao Indoh > <indou.takao@xxxxxxxxxxxxxx> wrote: >> (2013/06/11 11:20), Bjorn Helgaas wrote: > >>> I'm not sure you need to reset legacy devices (or non-PCI devices) >>> yet, but the current hook isn't anchored anywhere -- it's just an >>> fs_initcall() that doesn't give the reader any clue about the >>> connection between the reset and the problem it's solving. >>> >>> If we do something like this patch, I think it needs to be done at the >>> point where we enable or disable the IOMMU. That way, it's connected >>> to the important event, and there's a clue about how to make >>> corresponding fixes for other IOMMUs. >> >> Ok. pci_iommu_init() is appropriate place to add this hook? > > I looked at various IOMMU init places today, and it's far more > complicated and varied than I had hoped. > > This reset scheme depends on enumerating PCI devices before we > initialize the IOMMU used by those devices. x86 works that way today, > but not all architectures do (see the sparc pci_fire_pbm_init(), for Sorry, could you tell me which part depends on architecture? > example). And I think conceptually, the IOMMU should be enumerated > and initialized *before* the devices that use it. > > So I'm uncomfortable with that aspect of this scheme. > > It would be at least conceivable to reset the devices in the system > kernel, before the kexec. I know we want to do as little as possible > in the crashing kernel, but it's at least a possibility, and it might > be cleaner. I bet this will be not accepted by kdump maintainer. Everything in panic kernel is unreliable. Thanks, Takao Indoh -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
