On Thu, 2022-06-02 at 15:42 +0200, Markus Kolb wrote: [...] > In the patches > > > https://salsa.debian.org/kernel-team/linux/-/blob/bullseye-security/debian/patches/features/x86/intel-iommu-add-kconfig-option-to-exclude-igpu-by-default.patch > > https://salsa.debian.org/kernel-team/linux/-/blob/bullseye-security/debian/patches/features/x86/intel-iommu-add-option-to-exclude-integrated-gpu-only.patch > > there is introduced the kernel config option > INTEL_IOMMU_DEFAULT_ON_INTGPU_OFF > but it is not handled anywhere in the code.
It is handled implicitly. When that config symbol is enabled, both INTEL_IOMMU_DEFAULT_ON and INTEL_IOMMU_DEFAULT_OFF are disabled. > I think you have mixed up the defaults of the configuration and settings > of igfx_off and intgpu_off somehow which sets something up resulting in > a wrong config for my boot. intgpu_off boot config itself doesn't change > anything, with the Debian kernel I need igfx_off. > > At > > https://salsa.debian.org/kernel-team/linux/-/blob/bullseye-security/debian/patches/features/x86/intel-iommu-add-option-to-exclude-integrated-gpu-only.patch#L66 > you should compare 10 chars and not only 8, but is more or less > correctness. Well spotted. This is because at some point in development I changed the name of the option from igpu_off to intgpu_off. The patch description also has the earlier name. I'll correct that. > Maybe this > static int dmar_map_intgpu = > IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_ON); > at > > https://salsa.debian.org/kernel-team/linux/-/blob/bullseye-security/debian/patches/features/x86/intel-iommu-add-kconfig-option-to-exclude-igpu-by-default.patch#L74 > should be > static int dmar_map_intgpu = > IS_ENABLED(INTEL_IOMMU_DEFAULT_ON_INTGPU_OFF); No, the whole point of INTEL_IOMMU_DEFAULT_ON_INTGPU_OFF is to turn that off by default while still enabling the IOMMU for other devices. Based on the log from your self-built kernel, it seems like your system should work with the kernel parameter "intel_iommu=on". Can you test whether that makes a difference with the Debian kernels? Ben. > or the negated value, not sure at the moment, what a y or n should mean > in this config and if the assignments of 0 or 1 are correct everywhere. -- Ben Hutchings Humour is the best antidote to reality.
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