From 2cda2e10dc8343ae01eae9e999a876b7e7d37861 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Naval=20Alcal=C3=A1?= Date: Sat, 9 May 2026 10:43:44 +0800 Subject: [PATCH] iommu/vt-d: Disable DMAR for Intel Q35 IGFX MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Intel Q35 integrated graphics (8086:29b2) exhibits broken DMAR behaviour similar to other G4x/GM45 devices for which DMAR is already disabled via quirks. When DMAR is enabled, the system may hard lock up during boot or early device initialization, requiring a reset. Add the missing PCI ID to the existing quirk list to disable DMAR for this device. Fixes: 1f76249cc3be ("iommu/vt-d: Declare Broadwell igfx dmar support snafu") Cc: stable@vger.kernel.org Closes: https://bugzilla.kernel.org/show_bug.cgi?id=201185 Closes: https://bugzilla.kernel.org/show_bug.cgi?id=216064 Signed-off-by: Naval Alcalá Link: https://lore.kernel.org/r/20260410161622.13549-1-ari@naval.cat Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/intel/iommu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index c3d18cd77d2f..2a6b6813a78d 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -3937,6 +3937,9 @@ static void quirk_iommu_igfx(struct pci_dev *dev) disable_igfx_iommu = 1; } +/* Q35 integrated gfx dmar support is totally busted. */ +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x29b2, quirk_iommu_igfx); + /* G4x/GM45 integrated gfx dmar support is totally busted. */ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2a40, quirk_iommu_igfx); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2e00, quirk_iommu_igfx);