On 4/2/2015 1:19 PM, Ingo Molnar wrote:
+ if (amd_gart_present()) amd_northbridges.flags |= AMD_NB_GART;/*diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c index 76164e173a24..1cb170b06853 100644 --- a/arch/x86/kernel/aperture_64.c +++ b/arch/x86/kernel/aperture_64.c @@ -262,7 +262,7 @@ void __init early_gart_iommu_check(void) u64 aper_base = 0, last_aper_base = 0; int aper_enabled = 0, last_aper_enabled = 0, last_valid = 0;- if (!early_pci_allowed())+ if (!early_pci_allowed() || !amd_gart_present()) return;/* This is mostly duplicate of iommu_hole_init */@@ -356,7 +356,7 @@ int __init gart_iommu_hole_init(void) int i, node;if (gart_iommu_aperture_disabled || !fix_aperture ||- !early_pci_allowed()) + !early_pci_allowed() || !amd_gart_present()) return -ENODEV;So what happens if !early_pci_allowed() but the GART is present? We'll set amd_northbridges.flags |= AMD_NB_GART, but won't run any of the setup code in aperture_64.c, right? Is that a valid setup?
It might be a valid setup. But it would work correctly only if BIOS did the right thing with setting up aperture space.
If !early_pci_allowed() and BIOS did not setup aperture correctly, that would have caused problems already.
But it has not been an issue so far right? Thanks, -Aravind. -- 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/
