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Commit 62edf5dc authored by David Woodhouse's avatar David Woodhouse
Browse files

intel-iommu: Restore DMAR_BROKEN_GFX_WA option for broken graphics drivers 



We need to give people a little more time to fix the broken drivers.
Re-introduce this, but tied in properly with the 'iommu=pt' support this
time. Change the config option name and make it default to 'no' too.

Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 40e4aa34

arch/x86/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -1913,6 +1913,18 @@ config DMAR_DEFAULT_ON 
	  recommended you say N here while the DMAR code remains

	  experimental.



config DMAR_BROKEN_GFX_WA

	def_bool n

	prompt "Workaround broken graphics drivers (going away soon)"

	depends on DMAR

	---help---

	  Current Graphics drivers tend to use physical address

	  for DMA and avoid using DMA APIs. Setting this config

	  option permits the IOMMU driver to set a unity map for

	  all the OS-visible memory. Hence the driver can continue

	  to use physical addresses for DMA, at least until this

	  option is removed in the 2.6.32 kernel.



config DMAR_FLOPPY_WA

	def_bool y

	depends on DMAR

drivers/pci/intel-iommu.c

+19 −10
Original line number Diff line number Diff line
@@ -2127,6 +2127,7 @@ static int iommu_prepare_static_identity_mapping(void) 
		return -EFAULT;



	for_each_pci_dev(pdev) {

		if (iommu_identity_mapping == 1 || IS_GFX_DEVICE(pdev)) {

			printk(KERN_INFO "IOMMU: identity mapping for device %s\n",

			       pci_name(pdev));
@@ -2138,6 +2139,7 @@ static int iommu_prepare_static_identity_mapping(void) 
			if (ret)

				return ret;

		}

	}



	return 0;

}
@@ -2291,6 +2293,10 @@ int __init init_dmars(void) 
	 * identity mapping if iommu_identity_mapping is set.

	 */

	if (!iommu_pass_through) {

#ifdef CONFIG_DMAR_BROKEN_GFX_WA

		if (!iommu_identity_mapping)

			iommu_identity_mapping = 2;

#endif

		if (iommu_identity_mapping)

			iommu_prepare_static_identity_mapping();

		/*
@@ -2444,6 +2450,9 @@ static int iommu_dummy(struct pci_dev *pdev) 


static int iommu_should_identity_map(struct pci_dev *pdev)

{

	if (iommu_identity_mapping == 2)

		return IS_GFX_DEVICE(pdev);

	else

		return pdev->dma_mask > DMA_BIT_MASK(32);

}