Eric Lee / linux-smarc-t335x-v3.2

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Commit 0cd5c3c80a0ebd68c08312fa7d8c13149cc61c4c

Authored by Kyle McMartin
Committed by Ingo Molnar
1 parent b534816b55
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

x86: disable intel_iommu support by default 

Due to recurring issues with DMAR support on certain platforms.
There's a number of filesystem corruption incidents reported:

  https://bugzilla.redhat.com/show_bug.cgi?id=479996
  http://bugzilla.kernel.org/show_bug.cgi?id=12578

Provide a Kconfig option to change whether it is enabled by
default.

If disabled, it can still be reenabled by passing intel_iommu=on to the
kernel. Keep the .config option off by default.

Signed-off-by: Kyle McMartin <kyle@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-By: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 3 changed files with 24 additions and 3 deletions Side-by-side Diff

Documentation/kernel-parameters.txt
Diff comments   View file @ 0cd5c3c
... ... @@ -937,6 +937,8 @@
937 937  
938 938  
939 939 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
  940 + on
  941 + Enable intel iommu driver.
940 942 off
941 943 Disable intel iommu driver.
942 944 igfx_off [Default Off]
... ... @@ -1802,6 +1802,17 @@
1802 1802 and include PCI device scope covered by these DMA
1803 1803 remapping devices.
1804 1804  
  1805 +config DMAR_DEFAULT_ON
  1806 + def_bool n
  1807 + prompt "Enable DMA Remapping Devices by default"
  1808 + depends on DMAR
  1809 + help
  1810 + Selecting this option will enable a DMAR device at boot time if
  1811 + one is found. If this option is not selected, DMAR support can
  1812 + be enabled by passing intel_iommu=on to the kernel. It is
  1813 + recommended you say N here while the DMAR code remains
  1814 + experimental.
  1815 +
1805 1816 config DMAR_GFX_WA
1806 1817 def_bool y
1807 1818 prompt "Support for Graphics workaround"
drivers/pci/intel-iommu.c
Diff comments   View file @ 0cd5c3c
... ... @@ -268,7 +268,12 @@
268 268  
269 269 static void domain_remove_dev_info(struct dmar_domain *domain);
270 270  
271   -int dmar_disabled;
  271 +#ifdef CONFIG_DMAR_DEFAULT_ON
  272 +int dmar_disabled = 0;
  273 +#else
  274 +int dmar_disabled = 1;
  275 +#endif /*CONFIG_DMAR_DEFAULT_ON*/
  276 +
272 277 static int __initdata dmar_map_gfx = 1;
273 278 static int dmar_forcedac;
274 279 static int intel_iommu_strict;
275 280  
... ... @@ -284,9 +289,12 @@
284 289 if (!str)
285 290 return -EINVAL;
286 291 while (*str) {
287   - if (!strncmp(str, "off", 3)) {
  292 + if (!strncmp(str, "on", 2)) {
  293 + dmar_disabled = 0;
  294 + printk(KERN_INFO "Intel-IOMMU: enabled\n");
  295 + } else if (!strncmp(str, "off", 3)) {
288 296 dmar_disabled = 1;
289   - printk(KERN_INFO"Intel-IOMMU: disabled\n");
  297 + printk(KERN_INFO "Intel-IOMMU: disabled\n");
290 298 } else if (!strncmp(str, "igfx_off", 8)) {
291 299 dmar_map_gfx = 0;
292 300 printk(KERN_INFO