From 6e6feb19cd092e7c8ca6a54bc1f64ee9cbc6a203 Mon Sep 17 00:00:00 2001 From: "Chia-Lin Kao (AceLan)" Date: Mon, 12 Jan 2026 16:32:50 +0800 Subject: [PATCH] UBUNTU: SAUCE: iommu/intel: disable DMAR for CFL and WHL integrated gfx BugLink: https://bugs.launchpad.net/bugs/2136958 This patch addresses screen flickering issues on systems with CoffeeLake and WhiskeyLake integrated graphics, identified under Ubuntu kernel version 6.8.0-x. Similar to the issues seen with Skylake, KabyLake, and CometLake, the flickering is caused by changes to the Ubuntu kernel configuration, specifically the enabling of CONFIG_INTEL_IOMMU_DEFAULT_ON and CONFIG_INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON. The problem persists in the latest drm tip, and there is an upstream bug addressing the issue. https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/11504 Before there is a real fix for the issue, we add the affected GPU IDs to the quirk to disable their DMAR. Signed-off-by: Chia-Lin Kao (AceLan) --- drivers/iommu/intel/iommu.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 3043eceebbc9d..9873e0567e941 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -5115,6 +5115,31 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9B41, quirk_iommu_igfx); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9BCA, quirk_iommu_igfx); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9BCC, quirk_iommu_igfx); +/* CFL */ +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E90, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E91, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E92, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E93, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E94, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E96, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E98, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E99, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E9A, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E9B, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3E9C, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA5, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA6, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA7, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA8, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA9, quirk_iommu_igfx); + +/* WHL */ +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA0, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA1, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA2, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA3, quirk_iommu_igfx); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3EA4, quirk_iommu_igfx); + /* disable IPU dmar support */ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, quirk_iommu_ipu); -- 2.51.0