From 1b373f3559bbc2e7439b6a080da83ea8cd2de73c Mon Sep 17 00:00:00 2001 From: Frank Date: Sun, 18 Oct 2026 01:22:59 -0700 Subject: [PATCH] =?UTF-8?q?feat(dankclaw):=20boot=20with=20iommu=3Dpt=20?= =?UTF-8?q?=E2=80=94=20identity=20DMA,=20IOMMU=20stays=20armed?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 2026-09-11 trade bought a vendor-claimed 13-16% prefill figure that was never measured here; the 2026-10-18 research (same decision record) shows what identity mode actually costs the iGPU is the 1:1 page walk plus ATS/PRI/PASID/ GCR3 -- worth 2-4% on this silicon class, and removable outright by AMD PerfOpt when the distro ships Linux 7.4. Meanwhile pt is what err=-19 asks for: the XDNA2 NPU binds its own IOPT_TYPE_SVA domain and only needs the IOMMU enabled. Measured off-vs-pt prefill arms follow in the docs commit; frank-archon (Dankserver) is untouched. --- dankclaw/host/grub | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/dankclaw/host/grub b/dankclaw/host/grub index 1515f69..7bf4aec 100644 --- a/dankclaw/host/grub +++ b/dankclaw/host/grub @@ -7,8 +7,11 @@ GRUB_DEFAULT=0 GRUB_TIMEOUT_STYLE=hidden GRUB_TIMEOUT=0 GRUB_DISTRIBUTOR=`( . /etc/os-release && echo ${NAME} )` -GRUB_CMDLINE_LINUX_DEFAULT="quiet splash amd_iommu=off" -GRUB_CMDLINE_LINUX="" +# Identity (passthrough) DMA since 2026-10-18: the IOMMU stays enabled, so the +# XDNA2 NPU (/dev/accel/accel0, PASID/SVA) is usable again, while the iGPU's DMA +# runs untranslated. Decided in serverAppConfigs-docs/LLM/ +# dankclaw-iommu-translation-off.md; install with scripts/set-dankclaw-bootline.sh. +GRUB_CMDLINE_LINUX_DEFAULT="quiet splash iommu=pt" # If your computer has multiple operating systems installed, then you # probably want to run os-prober. However, if your computer is a host