Currently, AMD system will not boot if the AMD IOMMU driver initialization
fails. This is mainly due to devices' dma_ops are still configured to use
amd_iommu_ops. Instead, the driver should retore the device dma_ops to
the default one as part of its error recovery.
However, other clean ups should also be taken care of (e.g. removing
IOMMU groups, and unsetting bus IOMMU).
NOTE: This issue was found when booting Linux with pci=nomsi option.
Since the AMD IOMMU requires MSI, this result in failure to
initialize IOMMU interrupt.
Thanks,
Suravee
Suravee Suthikulpanit (2):
iommu: Introduce interface for unsetting bus IOMMU
iommu/amd: Fallback to dma_direct_ops when fail to enable IOMMU
drivers/iommu/amd_iommu.c | 14 +++++++++++++-
drivers/iommu/amd_iommu_init.c | 19 +++++++++++++++++--
drivers/iommu/amd_iommu_proto.h | 2 ++
drivers/iommu/iommu.c | 22 ++++++++++++++++++++++
include/linux/device.h | 1 +
include/linux/iommu.h | 1 +
6 files changed, 56 insertions(+), 3 deletions(-)
--
2.7.4
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