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authorSuresh Siddha <suresh.b.siddha@intel.com>2008-03-25 20:39:12 -0400
committerIngo Molnar <mingo@elte.hu>2008-03-26 17:23:41 -0400
commitd546b67a940eb42a99f56b86c5cd8d47c8348c2a (patch)
tree5382b2d1800756aedad0a25643081de2eec6a4bf /arch/x86/mm/pageattr.c
parent76c324182bbd29dfe4298ca65efb15be18055df1 (diff)
x86: fix performance drop for glx
fix the 3D performance drop reported at: http://bugzilla.kernel.org/show_bug.cgi?id=10328 fb drivers are using ioremap()/ioremap_nocache(), followed by mtrr_add with WC attribute. Recent changes in page attribute code made both ioremap()/ioremap_nocache() mappings as UC (instead of previous UC-). This breaks the graphics performance, as the effective memory type is UC instead of expected WC. The correct way to fix this is to add ioremap_wc() (which uses UC- in the absence of PAT kernel support and WC with PAT) and change all the fb drivers to use this new ioremap_wc() API. We can take this correct and longer route for post 2.6.25. For now, revert back to the UC- behavior for ioremap/ioremap_nocache. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/mm/pageattr.c')
-rw-r--r--arch/x86/mm/pageattr.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 14e48b5a94ba..7b79f6be4e7d 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -771,7 +771,7 @@ static inline int change_page_attr_clear(unsigned long addr, int numpages,
771int set_memory_uc(unsigned long addr, int numpages) 771int set_memory_uc(unsigned long addr, int numpages)
772{ 772{
773 return change_page_attr_set(addr, numpages, 773 return change_page_attr_set(addr, numpages,
774 __pgprot(_PAGE_PCD | _PAGE_PWT)); 774 __pgprot(_PAGE_PCD));
775} 775}
776EXPORT_SYMBOL(set_memory_uc); 776EXPORT_SYMBOL(set_memory_uc);
777 777