Disable unmatched stream bypass by default
configname: CONFIG_ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT
Linux Kernel Configuration
└─>Device Drivers
└─>IOMMU Hardware Support
└─>Disable unmatched stream bypass by default
In linux kernel since version 4.14.326 (release Date: 2023-09-23)
If your firmware is broken and fails to describe StreamIDs which
Linux should know about in order to manage the SMMU correctly and
securely, and you don't want to boot with the 'arm-smmu.disable_bypass=0'
command line parameter, then as a last resort you can turn it off
by default here. But don't. This option may be removed at any time.
Note that 'arm-smmu.disable_bypass=1' will still take precedence.
Linux should know about in order to manage the SMMU correctly and
securely, and you don't want to boot with the 'arm-smmu.disable_bypass=0'
command line parameter, then as a last resort you can turn it off
by default here. But don't. This option may be removed at any time.
Note that 'arm-smmu.disable_bypass=1' will still take precedence.