The patch titled
x86: allow intel_iommu support to be disabled by default
has been added to the -mm tree. Its filename is
x86-allow-intel_iommu-support-to-be-disabled-by-default.patch
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Subject: x86: allow intel_iommu support to be disabled by default
From: Kyle McMartin <kyle@xxxxxxxxxx>
Due to recurring issues with DMAR support on certain platforms, provide a
Kconfig option to change whether it is enabled by default. If disabled,
it can be reenabled by passing intel_iommu=on to the kernel.
Signed-off-by: Kyle McMartin <kyle@xxxxxxxxxx>
Cc: Mark McLoughlin <markmc@xxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.28.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 2 ++
arch/x86/Kconfig | 11 +++++++++++
drivers/pci/intel-iommu.c | 14 +++++++++++---
3 files changed, 24 insertions(+), 3 deletions(-)
diff -puN Documentation/kernel-parameters.txt~x86-allow-intel_iommu-support-to-be-disabled-by-default Documentation/kernel-parameters.txt
--- a/Documentation/kernel-parameters.txt~x86-allow-intel_iommu-support-to-be-disabled-by-default
+++ a/Documentation/kernel-parameters.txt
@@ -938,6 +938,8 @@ and is between 256 and 4096 characters.
intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
+ on
+ Enable intel iommu driver.
off
Disable intel iommu driver.
igfx_off [Default Off]
diff -puN arch/x86/Kconfig~x86-allow-intel_iommu-support-to-be-disabled-by-default arch/x86/Kconfig
--- a/arch/x86/Kconfig~x86-allow-intel_iommu-support-to-be-disabled-by-default
+++ a/arch/x86/Kconfig
@@ -1811,6 +1811,17 @@ config DMAR
and include PCI device scope covered by these DMA
remapping devices.
+config DMAR_DEFAULT_ON
+ def_bool n
+ prompt " Enable DMA Remapping Devices by default"
+ depends on DMAR
+ help
+ Selecting this option will enable a DMAR device at boot time if
+ one is found. If this option is not selected, DMAR support can
+ be enabled by passing intel_iommu=on to the kernel. It is
+ recommended you say N here while the DMAR code remains
+ experimental.
+
config DMAR_GFX_WA
def_bool y
prompt "Support for Graphics workaround"
diff -puN drivers/pci/intel-iommu.c~x86-allow-intel_iommu-support-to-be-disabled-by-default drivers/pci/intel-iommu.c
--- a/drivers/pci/intel-iommu.c~x86-allow-intel_iommu-support-to-be-disabled-by-default
+++ a/drivers/pci/intel-iommu.c
@@ -268,7 +268,12 @@ static long list_size;
static void domain_remove_dev_info(struct dmar_domain *domain);
-int dmar_disabled;
+#ifdef CONFIG_DMAR_DEFAULT_ON
+int dmar_disabled = 0;
+#else
+int dmar_disabled = 1;
+#endif /*CONFIG_DMAR_DEFAULT_ON*/
+
static int __initdata dmar_map_gfx = 1;
static int dmar_forcedac;
static int intel_iommu_strict;
@@ -284,9 +289,12 @@ static int __init intel_iommu_setup(char
if (!str)
return -EINVAL;
while (*str) {
- if (!strncmp(str, "off", 3)) {
+ if (!strncmp(str, "on", 2)) {
+ dmar_disabled = 0;
+ printk(KERN_INFO "Intel-IOMMU: enabled\n");
+ } else if (!strncmp(str, "off", 3)) {
dmar_disabled = 1;
- printk(KERN_INFO"Intel-IOMMU: disabled\n");
+ printk(KERN_INFO "Intel-IOMMU: disabled\n");
} else if (!strncmp(str, "igfx_off", 8)) {
dmar_map_gfx = 0;
printk(KERN_INFO
_
Patches currently in -mm which might be from kyle@xxxxxxxxxx are
x86-allow-intel_iommu-support-to-be-disabled-by-default.patch
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