Commit:     7d3b03ce7bff9d39ebaee1bb8de1968c4434b883
Parent:     eb3fa7cb51a2a35cd95eb92e65d8039c779468a5
Author:     Keshavamurthy, Anil S <[EMAIL PROTECTED]>
AuthorDate: Sun Oct 21 16:41:53 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon Oct 22 08:13:18 2007 -0700

    Intel IOMMU: Intel iommu cmdline option - forcedac
    Introduce intel_iommu=forcedac commandline option.  This option is helpful 
    verify the pci device capability of handling physical dma'able address 
    than 4G.
    Signed-off-by: Anil S Keshavamurthy <[EMAIL PROTECTED]>
    Cc: Andi Kleen <[EMAIL PROTECTED]>
    Cc: Peter Zijlstra <[EMAIL PROTECTED]>
    Cc: Muli Ben-Yehuda <[EMAIL PROTECTED]>
    Cc: "Siddha, Suresh B" <[EMAIL PROTECTED]>
    Cc: Arjan van de Ven <[EMAIL PROTECTED]>
    Cc: Ashok Raj <[EMAIL PROTECTED]>
    Cc: "David S. Miller" <[EMAIL PROTECTED]>
    Cc: Christoph Lameter <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
 Documentation/kernel-parameters.txt |    7 +++++++
 drivers/pci/intel-iommu.c           |    7 ++++++-
 2 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/Documentation/kernel-parameters.txt 
index 8157417..b236166 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -781,6 +781,13 @@ and is between 256 and 4096 characters. It is defined in 
the file
                        bypassed by not enabling DMAR with this option. In
                        this case, gfx device will use physical address for
+               forcedac [x86_64]
+                       With this option iommu will not optimize to look
+                       for io virtual address below 32 bit forcing dual
+                       address cycle on pci bus for cards supporting greater
+                       than 32 bit addressing. The default is to look
+                       for translation below 32 bit and if not available
+                       then look in the higher range.
        io7=            [HW] IO7 for Marvel based alpha systems
                        See comment before marvel_specify_io7 in
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 05630b4..cb24def 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -54,6 +54,7 @@ static void domain_remove_dev_info(struct dmar_domain 
 static int dmar_disabled;
 static int __initdata dmar_map_gfx = 1;
+static int dmar_forcedac;
 #define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1))
 static DEFINE_SPINLOCK(device_domain_lock);
@@ -71,6 +72,10 @@ static int __init intel_iommu_setup(char *str)
                        dmar_map_gfx = 0;
                                "Intel-IOMMU: disable GFX device mapping\n");
+               } else if (!strncmp(str, "forcedac", 8)) {
+                       printk (KERN_INFO
+                               "Intel-IOMMU: Forcing DAC for PCI devices\n");
+                       dmar_forcedac = 1;
                str += strcspn(str, ",");
@@ -1558,7 +1563,7 @@ static dma_addr_t __intel_map_single(struct device *dev, 
void *addr,
        start_addr = IOVA_START_ADDR;
-       if (pdev->dma_mask <= DMA_32BIT_MASK) {
+       if ((pdev->dma_mask <= DMA_32BIT_MASK) || (dmar_forcedac)) {
                iova = iommu_alloc_iova(domain, addr, size, start_addr,
        } else  {
To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at

Reply via email to