From: David Woodhouse Date: Mon, 17 Oct 2011 22:51:52 +0000 (-0700) Subject: intel-iommu: Workaround IOTLB hang on Ironlake GPU X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d15bf23bc025ded52054ac3a05d6433a54e43fd2;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git intel-iommu: Workaround IOTLB hang on Ironlake GPU To work around a hardware issue, we have to submit IOTLB flushes while the graphics engine is idle. The graphics driver will (we hope) go to great lengths to ensure that it gets that right on the affected chipset(s)... so let's not screw it over by deferring the unmap and doing it later. That wouldn't be very helpful. Signed-off-by: David Woodhouse Signed-off-by: Ben Widawsky Signed-off-by: Keith Packard --- diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index c621c98c99da..ff266034ead8 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -3950,7 +3950,11 @@ static void __devinit quirk_calpella_no_shadow_gtt(struct pci_dev *dev) if (!(ggc & GGC_MEMORY_VT_ENABLED)) { printk(KERN_INFO "DMAR: BIOS has allocated no shadow GTT; disabling IOMMU for graphics\n"); dmar_map_gfx = 0; - } + } else if (dmar_map_gfx) { + /* we have to ensure the gfx device is idle before we flush */ + printk(KERN_INFO "DMAR: Disabling batched IOTLB flush on Ironlake\n"); + intel_iommu_strict = 1; + } } DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0040, quirk_calpella_no_shadow_gtt); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0044, quirk_calpella_no_shadow_gtt);