x86: Gart: fix breakage due to IOMMU initialization cleanup

This fixes the following breakage of the commit
75f1cdf1dda92cae037ec848ae63690d91913eac:

- GART systems that don't AGP with broken BIOS and more than 4GB
  memory are forced to use swiotlb. They can allocate aperture by
  hand and use GART.

- GART systems without GAP must disable GART on shutdown.

- swiotlb usage is forced by the boot option,
  gart_iommu_hole_init() is not called, so we disable GART
  early_gart_iommu_check().

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
LKML-Reference: <1260759135-6450-3-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 6 insertions, 5 deletions

diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index e0dfb6856aa2..3704997e8b25 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -280,7 +280,8 @@ void __init early_gart_iommu_check(void)
          * or BIOS forget to put that in reserved.
          * try to update e820 to make that region as reserved.
          */
-        int i, fix, slot;
+        u32 agp_aper_base = 0, agp_aper_order = 0;
+        int i, fix, slot, valid_agp = 0;
         u32 ctl;
         u32 aper_size = 0, aper_order = 0, last_aper_order = 0;
         u64 aper_base = 0, last_aper_base = 0;
@@ -290,6 +291,8 @@ void __init early_gart_iommu_check(void)
                 return;
 
         /* This is mostly duplicate of iommu_hole_init */
+        agp_aper_base = search_agp_bridge(&agp_aper_order, &valid_agp);
+
         fix = 0;
         for (i = 0; i < ARRAY_SIZE(bus_dev_ranges); i++) {
                 int bus;
@@ -342,10 +345,10 @@ void __init early_gart_iommu_check(void)
                 }
         }
 
-        if (!fix)
+        if (valid_agp)
                 return;
 
-        /* different nodes have different setting, disable them all at first*/
+        /* disable them all at first */
         for (i = 0; i < ARRAY_SIZE(bus_dev_ranges); i++) {
                 int bus;
                 int dev_base, dev_limit;
@@ -458,8 +461,6 @@ out:
 
         if (aper_alloc) {
                 /* Got the aperture from the AGP bridge */
-        } else if (!valid_agp) {
-                /* Do nothing */
         } else if ((!no_iommu && max_pfn > MAX_DMA32_PFN) ||
                    force_iommu ||
                    valid_agp ||