For devices stuck behind a conventional PCI bus, saving extra cycles at
33MHz is probably fairly significant. However since native PCI Express
is now the norm for high-performance devices, the optimisation to always
prefer 32-bit addresses for the sake of avoiding DAC is starting to look
rather ana
On Wed, May 18, 2022 at 06:36:59PM +0100, Robin Murphy wrote:
> +config IOMMU_DMA_PCI_SAC_OPT
> + bool "Enable 64-bit legacy PCI optimisation by default"
> + depends on IOMMU_DMA
> + default X86
> + help
> + Enable by default an IOMMU optimisation for 64-bit legacy PCI devices
On 18/05/2022 18:36, Robin Murphy wrote:
For devices stuck behind a conventional PCI bus, saving extra cycles at
33MHz is probably fairly significant. However since native PCI Express
is now the norm for high-performance devices, the optimisation to always
prefer 32-bit addresses for the sake of
