linux-fedora/linux-2.6-intel-iommu-igfx.patch

   1 From e13491e4c394907ffdd834aeccca279213818079 Mon Sep 17 00:00:00 2001
   2 From: drago01 <drago01@gmail.com>
   3 Date: Wed, 26 Oct 2011 13:37:27 -0400
   4 Subject: [PATCH] Default to igfx_off
   5
   6 This option seems to causes way to many issues, it is
   7 being investigated by Intel's chipset team for months now and
   8 we still don't have any outcome.
   9
  10 The results so far are "black screen when starting X",
  11 "system hangs when using GL", "system does not resume".
  12
  13 The patch adds an intel_iommu=igfx_on option, which makes it opt in,
  14 rather than opt out.
  15
  16 Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com>
  17 Reviewed-by: Adam Jackson <ajax@redhat.com>
  18 ---
  19  Documentation/kernel-parameters.txt |   11 +++++------
  20  drivers/iommu/intel-iommu.c         |    9 +++++----
  21  2 files changed, 10 insertions(+), 10 deletions(-)
  22
  23 diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
  24 index a8ba119..8ddc43a 100644
  25 --- a/Documentation/kernel-parameters.txt
  26 +++ b/Documentation/kernel-parameters.txt
  27 @@ -998,12 +998,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
  28                         Enable intel iommu driver.
  29                 off
  30                         Disable intel iommu driver.
  31 -               igfx_off [Default Off]
  32 -                       By default, gfx is mapped as normal device. If a gfx
  33 -                       device has a dedicated DMAR unit, the DMAR unit is
  34 -                       bypassed by not enabling DMAR with this option. In
  35 -                       this case, gfx device will use physical address for
  36 -                       DMA.
  37 +               igfx_on [Default Off]
  38 +                       By default, the gfx's DMAR unit is bypassed by not enabling
  39 +                       DMAR with this option. So the gfx device will use physical
  40 +                       address for DMA. When this option is enabled it the gfx is
  41 +                       mapped as normal device.
  42                 forcedac [x86_64]
  43                         With this option iommu will not optimize to look
  44                         for io virtual address below 32-bit forcing dual
  45 diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
  46 index be1953c..2e23af1 100644
  47 --- a/drivers/iommu/intel-iommu.c
  48 +++ b/drivers/iommu/intel-iommu.c
  49 @@ -404,7 +404,8 @@ int dmar_disabled = 0;
  50  int dmar_disabled = 1;
  51  #endif /*CONFIG_INTEL_IOMMU_DEFAULT_ON*/
  52
  53 -static int dmar_map_gfx = 1;
  54 +/* disabled by default; causes way too many issues */
  55 +static int dmar_map_gfx = 0;
  56  static int dmar_forcedac;
  57  static int intel_iommu_strict;
  58  static int intel_iommu_superpage = 1;
  59 @@ -429,10 +430,10 @@ static int __init intel_iommu_setup(char *str)
  60                 } else if (!strncmp(str, "off", 3)) {
  61                         dmar_disabled = 1;
  62                         printk(KERN_INFO "Intel-IOMMU: disabled\n");
  63 -               } else if (!strncmp(str, "igfx_off", 8)) {
  64 -                       dmar_map_gfx = 0;
  65 +               } else if (!strncmp(str, "igfx_on", 7)) {
  66 +                       dmar_map_gfx = 1;
  67                         printk(KERN_INFO
  68 -                               "Intel-IOMMU: disable GFX device mapping\n");
  69 +                               "Intel-IOMMU: enabled GFX device mapping\n");
  70                 } else if (!strncmp(str, "forcedac", 8)) {
  71                         printk(KERN_INFO
  72                                 "Intel-IOMMU: Forcing DAC for PCI devices\n");
  73 --
  74 1.7.6.4
  75