From: Joerg Roedel <jroedel@suse.de>
Date: Tue, 11 Jul 2017 15:48:00 -0500
Subject: PCI: Mark AMD Stoney GPU ATS as broken
Git-commit: 9b44b0b09decfbe388131a345ba780c57240a7a9
Patch-mainline: v4.14-rc1
References: bsc#1085438

ATS is broken on this hardware and causes IOMMU stalls and system failure.
Disable ATS on these devices to make them usable again with IOMMU enabled.

Note that the commit in the Fixes tag is not buggy; it just uncovers the
problem in the hardware by increasing the ATS flush rate.

Link: https://lists.linuxfoundation.org/pipermail/iommu/2017-March/020836.html
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1409201
Fixes: b1516a14657a ("iommu/amd: Implement flush queue")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/pci/quirks.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4809,6 +4809,21 @@ static void quirk_intel_no_flr(struct pc
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1502, quirk_intel_no_flr);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1503, quirk_intel_no_flr);
 
+#ifdef CONFIG_PCI_ATS
+/*
+ * Some devices have a broken ATS implementation causing IOMMU stalls.
+ * Don't use ATS for those devices.
+ */
+static void quirk_no_ats(struct pci_dev *pdev)
+{
+	dev_info(&pdev->dev, "disabling ATS (broken on this device)\n");
+	pdev->ats_cap = 0;
+}
+
+/* AMD Stoney platform GPU */
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x98e4, quirk_no_ats);
+#endif /* CONFIG_PCI_ATS */
+
 static void quirk_no_ext_tags(struct pci_dev *pdev)
 {
 	struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus);