diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 48 |
1 files changed, 32 insertions, 16 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 8c22943e51c0..f2fff89bc7bb 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2580,23 +2580,41 @@ Kernel parameters Don't force hardware IOMMU usage when it is not needed. (default). + merge + Do scatter-gather (SG) merging. Implies "force" + (experimental). + + nomerge + Don't do scatter-gather (SG) merging. + biomerge + Do scatter-gather (SG) merging. Implies "force" + (experimental). [same as "merge"] + panic + Always panic when IOMMU overflows. + nopanic - merge - nomerge + Don't panic on IOMMU overflows. + + pt + Use passththrough mode by default + (Equivalent to iommu.passthrough=1) + + nopt + Use translated mode for DMA by default + (Equivalent to iommu.passthrough=0) soft Use software bounce buffering (SWIOTLB) (default for Intel machines). This can be used to prevent the usage of an available hardware IOMMU. - pt - nopt - nobypass [PPC/POWERNV] - Disable IOMMU bypass, using IOMMU for PCI devices. + usedac + Use the DAC on VIA PCI bridge + (default: disable the VIA PCI bridge DAC) - AMD Gart HW IOMMU-specific options: + AMD Gart HW IOMMU-specific options: (CONFIG_GART_IOMMU) <size> Set the size of the remapping area in bytes. @@ -2604,6 +2622,9 @@ Kernel parameters allowed Overwrite iommu off workarounds for specific chipsets + force + Overwrite iommu off workarounds for specific chipsets + fullflush Flush IOMMU on each allocation (default). @@ -2614,21 +2635,16 @@ Kernel parameters Allocate an own aperture over RAM with size 32MB<<order. (default: order=1, i.e. 64MB) - merge - Do scatter-gather (SG) merging. Implies "force" - (experimental). - - nomerge - Don't do scatter-gather (SG) merging. - noaperture Ask the IOMMU not to touch the aperture for AGP. noagp Don't initialize the AGP driver and use full aperture. - panic - Always panic when IOMMU overflows. + iommu= [PPC/POWERNV] + + nobypass + Disable IOMMU bypass, using IOMMU for PCI devices. iommu.forcedac= [ARM64,X86,EARLY] Control IOVA allocation for PCI devices. Format: { "0" | "1" } |