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authorLinus Torvalds <torvalds@linux-foundation.org>2014-03-13 21:32:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-03-13 21:32:16 -0700
commitc60f7d5a8e7c639de5d9dfe07e1e91d302d506e4 (patch)
treec1d12d4963768232f3489f7dc5a6626ddd3d5fde /drivers/gpu/drm/ttm/ttm_bo_vm.c
parentMerge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux (diff)
parentMerge tag 'ttm-fixes-3.14-2014-03-12' of git://people.freedesktop.org/~thomash/linux into drm-fixes (diff)
downloadlinux-dev-c60f7d5a8e7c639de5d9dfe07e1e91d302d506e4.tar.xz
linux-dev-c60f7d5a8e7c639de5d9dfe07e1e91d302d506e4.zip
Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux
Pull drm fixes from Dave Airlie: "Pretty minor set of fixes for radeon, ttm and vmwgfx. The ttm ones are a regression and an oops seen on server chipsets" * 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: drm/vmwgfx: Fix a surface reference corner-case in legacy emulation mode drm/radeon/cik: properly set compute ring status on disable drm/radeon/cik: stop the sdma engines in the enable() function drm/radeon/cik: properly set sdma ring status on disable drm/radeon: fix runpm disabling on non-PX harder drm/ttm: don't oops if no invalidate_caches() drm/ttm: Work around performance regression with VM_PFNMAP
Diffstat (limited to '')
-rw-r--r--drivers/gpu/drm/ttm/ttm_bo_vm.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 801231c9ae48..0ce48e5a9cb4 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -339,11 +339,13 @@ int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
vma->vm_private_data = bo;
/*
- * PFNMAP is faster than MIXEDMAP due to reduced page
- * administration. So use MIXEDMAP only if private VMA, where
- * we need to support COW.
+ * We'd like to use VM_PFNMAP on shared mappings, where
+ * (vma->vm_flags & VM_SHARED) != 0, for performance reasons,
+ * but for some reason VM_PFNMAP + x86 PAT + write-combine is very
+ * bad for performance. Until that has been sorted out, use
+ * VM_MIXEDMAP on all mappings. See freedesktop.org bug #75719
*/
- vma->vm_flags |= (vma->vm_flags & VM_SHARED) ? VM_PFNMAP : VM_MIXEDMAP;
+ vma->vm_flags |= VM_MIXEDMAP;
vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
return 0;
out_unref:
@@ -359,7 +361,7 @@ int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
vma->vm_ops = &ttm_bo_vm_ops;
vma->vm_private_data = ttm_bo_reference(bo);
- vma->vm_flags |= (vma->vm_flags & VM_SHARED) ? VM_PFNMAP : VM_MIXEDMAP;
+ vma->vm_flags |= VM_MIXEDMAP;
vma->vm_flags |= VM_IO | VM_DONTEXPAND;
return 0;
}