agp/intel: restore cache behavior on sandybridge

This restores cache behavior for default AGP_USER_MEMORY as
uncached, and leave default AGP_USER_CACHED_MEMORY as LLC only.
I've seen different cache behavior on one sandybridge desktop CPU vs.
another mobile CPU. Until we figure out how to detect the real cache
config, restore back to the original behavior now.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 6b6760ea2435bac1865325aec74d579f9687f87e..791216d33ed0a6bd1a23e17fbb85c9e089e0dd6e 100644 (file)
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -1210,7 +1210,7 @@ static void gen6_write_entry(dma_addr_t addr, unsigned int entry,
        unsigned int gfdt = flags & AGP_USER_CACHED_MEMORY_GFDT;
        u32 pte_flags;
 
-       if (type_mask == AGP_USER_UNCACHED_MEMORY)
+       if (type_mask == AGP_USER_MEMORY)
                pte_flags = GEN6_PTE_UNCACHED | I810_PTE_VALID;
        else if (type_mask == AGP_USER_CACHED_MEMORY_LLC_MLC) {
                pte_flags = GEN6_PTE_LLC | I810_PTE_VALID;