redonkable/alistair23-linux
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drm: Use pgprot_writecombine in GEM GTT mapping to get the right bits for !PAT.

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Otherwise, the PAGE_CACHE_WC would end up getting us a UC-only mapping, and
the write performance of GTT maps dropped 10x.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[anholt: cleaned up unused var]
Signed-off-by: Eric Anholt <eric@anholt.net>
This commit is contained in:
Jesse Barnes 2009-03-31 18:22:31 -07:00 committed by Eric Anholt
parent 5e118f4139
commit 1055f9ddad
1 changed files with 1 additions and 6 deletions
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7
drivers/gpu/drm/drm_gem.c
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@ -505,7 +505,6 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
struct drm_local_map *map = NULL;
struct drm_gem_object *obj;
struct drm_hash_item *hash;
unsigned long prot;
int ret = 0;
mutex_lock(&dev->struct_mutex);
@ -538,11 +537,7 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
vma->vm_ops = obj->dev->driver->gem_vm_ops;
vma->vm_private_data = map->handle;
/* FIXME: use pgprot_writecombine when available */
prot = pgprot_val(vma->vm_page_prot);
#ifdef CONFIG_X86
prot |= _PAGE_CACHE_WC;
#endif
vma->vm_page_prot = __pgprot(prot);
vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
/* Take a ref for this mapping of the object, so that the fault
* handler can dereference the mmap offset's pointer to the object.