We have reports of heavy screen corruption if we try to use the stolen
memory reserved by the BIOS whilst the DMA-Remapper is active. This
quirk may be only specific to a few machines or BIOSes, but first lets
apply the big hammer and always disable use of stolen memory when DMAR
is active.

v2 by Jani: Rebase on -fixes, only look at intel_iommu_gfx_mapped.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68535Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

There is a conflict seen when requesting the kernel to reserve
the physical space used for the stolen area. This is because
some BIOS are wrapping the stolen area in the root PCI bus, but have
an off-by-one error. As a workaround we retry the reservation with an
offset of 1 instead of 0.

v2: updated commit message & the comment in source file (Daniel)
Signed-off-by: NAkash Goel <akash.goel@intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The 'offset' field of the 'scatterlist' structure was wrongly
programmed with the offset value from the base of stolen area,
whereas this field indicates the offset from where the interested
data starts within the first PAGE pointed to by 'scattterlist'
structure. As a result when a new GEM object allocated from stolen
area is mapped to GTT, it could lead to an overwrite of GTT entries
as the page count calculation will go wrong, refer the function
'sg_page_count'.

v2: Modified the commit message. (Chris)
Signed-off-by: NAkash Goel <akash.goel@intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71908
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=69104Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

But only when we indeed set up a gtt mapping. We need this since the
vma also holds a pages_pin_count, on top of the unconditional
pages_pin_count we grab for all stolen objects (to avoid swap-out).

This should avoid a pages_pin_count underrun when cleaning up
framebuffers objects taken over from the BIOS.

Chris mentioned in his review that this bug even predates the vma
conversion.
Reported-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Paulo reported that if he set the amount of reserved memory to 0, then
we emitted a warning about a conflict before disabling our use of stolen
memory. This was introduced with

commit eaba1b8f
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Jul 4 12:28:35 2013 +0100

    drm/i915: Verify that our stolen memory doesn't conflict

and is simply fixed by checking for a no reservation first.
Reported-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In the execbuf code we don't clean up any vmas which ended up not
getting bound for code simplicity. To make sure that we don't end up
creating multiple vma for the same vm kill the somewhat dangerous
vma_create function and inline it into lookup_or_create.

This is just a safety measure to prevent surprises in the future.

Also update the somewhat confused comment in the execbuf code and
clarify what kind of magic is going on with a new one.

v2: Keep the function separate as requested by Chris. But give it a __
prefix for paranoia and move it tighter together with the other vma
stuff.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Use the standard inversely ordered goto label stack for everything.
Spotted while reviewing place where we might need to to call
vma_destroy but failed to do so.

Cc: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As a corollary to reviewing the interaction between LLC and our cache
domains, the GPU PTE bits are independent of the CPU PAT bits. As such
we can set the cache level on stolen memory based on how we wish the GPU
to cache accesses to it. So we are free to set the same default cache
levels as for normal bo, i.e. enable LLC cacheing by default where
appropriate.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

formerly: "drm/i915: Create VMAs (part 5) - move mm_list"

The mm_list is used for the active/inactive LRUs. Since those LRUs are
per address space, the link should be per VMx .

Because we'll only ever have 1 VMA before this point, it's not incorrect
to defer this change until this point in the patch series, and doing it
here makes the change much easier to understand.

Shamelessly manipulated out of Daniel:
"active/inactive stuff is used by eviction when we run out of address
space, so needs to be per-vma and per-address space. Bound/unbound otoh
is used by the shrinker which only cares about the amount of memory used
and not one bit about in which address space this memory is all used in.
Of course to actual kick out an object we need to unbind it from every
address space, but for that we have the per-object list of vmas."

v2: only bump GGTT LRU in i915_gem_object_set_to_gtt_domain (Chris)

v3: Moved earlier in the series

v4: Add dropped message from v3
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Frob patch to apply and use vma->node.size directly as
discused with Ben. Also drop a needles BUG_ON before move_to_inactive,
the function itself has the same check.]
[danvet 2nd: Rebase on top of the lost "drm/i915: Cleanup more of VMA
in destroy", specifically unlink the vma from the mm_list in
vma_unbind (to keep it symmetric with bind_to_vm) instead of
vma_destroy.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

i915 is the last user of the weird search+get_block drm_mm API. Convert it
to an explicit kmalloc()+insert_node(). This drops the last user of the
node-cache in drm_mm. We can remove it now in a follow-up patch.

v2:
 - simplify error path in i915_setup_compression()
v3:
 - simplify error path even more

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Add a "best_match" flag similar to the drm_mm_search_*() helpers so we
can convert TTM to use them in follow up patches. We can also inline the
non-generic helpers and move them into the header to allow compile-time
optimizations.

To make calls to drm_mm_{search,insert}_node() more readable, this
converts the boolean argument to a flagset. There are pending patches that
add additional flags for top-down allocators and more.

v2:
 - use flag parameter instead of boolean "best_match"
 - convert *_search_free() helpers to also use flags argument
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Just some small cleanups, and a rename of vm->ggtt_vm requested by
Daniel.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

So I made the mistake of missing that the desktop and mobile chipsets
have different layouts in their PCI configurations, and we were
incorrectly setting the wrong physical address for stolen memory on
mobile chipsets.

Since all gen3+ are actually consistent in the location of the GBSM
register in the PCI configuration space on device 2 (the GPU), use it.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Drop cc: stable and fudge conflicts.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drm_gem_object_init() and drm_gem_private_object_init() do exactly the
same (except for shmem alloc) so make the first use the latter to reduce
code duplication.

Also drop the return code from drm_gem_private_object_init(). It seems
unlikely that we will extend it any time soon so no reason to keep it
around. This simplifies code paths in drivers, too.

Last but not least, fix gma500 to call drm_gem_object_release() before
freeing objects that were allocated via drm_gem_private_object_init().
That isn't actually necessary for now, but might be in the future.
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NPatrik Jakobsson <patrik.r.jakobsson@gmail.com>
Acked-by: NRob Clark <robdclark@gmail.com>
Signed-off-by: NDave Airlie <airlied@gmail.com>

i915_gem_vma_create() returns and ERR_PTR() or a valid pointer, it never
returns NULL.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Formerly: "drm/i915: Create VMAs (part 1)"

In a previous patch, the notion of a VM was introduced. A VMA describes
an area of part of the VM address space. A VMA is similar to the concept
in the linux mm. However, instead of representing regular memory, a VMA
is backed by a GEM BO. There may be many VMAs for a given object, one
for each VM the object is to be used in. This may occur through flink,
dma-buf, or a number of other transient states.

Currently the code depends on only 1 VMA per object, for the global GTT
(and aliasing PPGTT). The following patches will address this and make
the rest of the infrastructure more suited

v2: s/i915_obj/i915_gem_obj (Chris)

v3: Only move an object to the now global unbound list if there are no
more VMAs for the object which are bound into a VM (ie. the list is
empty).

v4: killed obj->gtt_space
some reworks due to rebase

v5: Free vma on error path (Imre)

v6: Another missed vma free in i915_gem_object_bind_to_gtt error path
(Imre)
Fixed vma freeing in stolen preallocation (Imre)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NImre Deak <imre.deak@intel.com>
[danvet: Squash in fixup from Ben to not deref a non-existing vma in
set_cache_level, reported by Chris.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The odds of this happening are *extremely* unlikely.
Reported-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Shamelessly manipulated out of Daniel :-)
"When moving the lists around explain that the active/inactive stuff is
used by eviction when we run out of address space, so needs to be
per-vma and per-address space. Bound/unbound otoh is used by the
shrinker which only cares about the amount of memory used and not one
bit about in which address space this memory is all used in. Of course
to actual kick out an object we need to unbind it from every address
space, but for that we have the per-object list of vmas."

v2: Leave the bound list as a global one. (Chris, indirectly)

v3: Rebased with no i915_gtt_vm. In most places I added a new *vm local,
since it will eventually be replaces by a vm argument.
Put comment back inline, since it no longer makes sense to do otherwise.

v4: Rebased on hangcheck/error state movement
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Every address space should support object allocation. It therefore makes
sense to have the allocator be part of the "superclass" which GGTT and
PPGTT will derive.

Since our maximum address space size is only 2GB we're not yet able to
avoid doing allocation/eviction; but we'd hope one day this becomes
almost irrelvant.

v2: Rebased
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Bail out if we hit the WARN_ON to avoid fallout later on. Spotted
by Chris Wilson.
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Sanity check that the memory region found through the Graphics Base
of Stolen Memory is reserved and hidden from the rest of the system
through the use of the resource API.

v2: "Graphics Stolen Memory" is such a more bodacious name than the lame
    "i915 stolen", and convert to using devres for automagical cleanup of
    the resource. (danvet)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Dump proper hexcodes.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Embedding the node in the obj is more natural in the transition to VMAs
which will also have embedded nodes. This change also helps transition
away from put_block to remove node.

Though it's quite an uncommon occurrence, it's somewhat convenient to not
fail at bind time because we cannot allocate the node. Though in
practice there are other allocations (like the request structure) which
would probably make this point not terribly useful.

Quoting Daniel:
Note that the only difference between put_block and remove_node is
that the former fills up the preallocation cache. Which we don't need
anyway and hence is just wasted space.

v2: Clean up the stolen preallocation code.
Rebased on the reserve_node patches
renames ggtt_ stuff to gtt_ stuff
WARN_ON if the object is already bound (which doesn't mean it's in the
bound list, tricky)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With the getters in place from the previous patch this members serves no
purpose other than saving one spare pointer chase, which will be killed
in the next patch anyway.

Moving to VMAs, this members adds unnecessary confusion since an object
may exist at different offsets in different VMs.

v2: Properly preserve the stolen offset. This code is a bit hacky but it
all goes away when we embed the drm_mm_node and removes the need for the
incorrect patch I submitted previously: "Use gtt_space->start for stolen
reservation"
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With the previous patch we no longer actually create a node, we simply
find the correct hole and occupy it. This very well could have been
squashed with the last patch, but since I already had David's review, I
figured it's easiest to keep it distinct.

Also update the users in i915. Conveniently this is the only user of the
interface.

CC: David Airlie <airlied@linux.ie>
CC: <dri-devel@lists.freedesktop.org>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Acked-by: NDavid Airlie <airlied@linux.ie>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

For an upcoming patch where we introduce the i915 VMA, it's ideal to
have the drm_mm_node as part of the VMA struct (ie. it's pre-allocated).
Part of the conversion to VMAs is to kill off obj->gtt_space. Doing this
will break a bunch of code, but amongst them are 2 callers of
drm_mm_create_block(), both related to stolen memory.

It also allows us to embed the drm_mm_node into the object currently
which provides a nice transition over to the new code.

v2: Reordered to do before ripping out obj->gtt_offset.
Some minor cleanups made available because of reordering.

v3: s/continue/break on failed stolen node allocation (David)
Set obj->gtt_space on failed node allocation (David)
Only unref stolen (fix double free) on failed create_stolen (David)
Free node, and NULL it in failed create_stolen (David)
Add back accidentally removed newline (David)

CC: <dri-devel@lists.freedesktop.org>
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Acked-by: NDavid Airlie <airlied@linux.ie>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

A magic -1 is a obscure, especially since it's actually passed as an
unsigned, so depends upon the magic sign extension rules in C. This has
been added in

commit 3727d55e
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Wed May 8 10:45:14 2013 -0700

    drm/i915: allow stolen, pre-allocated objects to avoid GTT allocation v2

Use a proper #define instead. Spotted while reviewing Ben's
drm_mm_create_block changes.

v2: Cast the constant to u32 since otherwise we again have a type
mismatch. Suggested by Chris Wilson.

Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Every other place properly checks whether we've managed to set
up the stolen allocator at boot-up properly, with the exception
of the cleanup code. Which results in an ugly

*ERROR* Memory manager not clean. Delaying takedown

at module unload time since the drm_mm isn't initialized at all.

v2: While at it check whether the stolen drm_mm is initialized instead
of the more obscure stolen_base == 0 check.

v3: Fix up the logic. Also we need to keep the stolen_base check in
i915_gem_object_create_stolen_for_preallocated since that can be
called before stolen memory is fully set up. Spotted by Chris Wilson.

v4: Readd the conversion in i915_gem_object_create_stolen_for_preallocated,
the check is for the dev_priv->mm.gtt_space drm_mm, the stolen
allocatot must already be initialized when calling that function (if
we indeed have stolen memory).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65953
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: lu hua <huax.lu@intel.com> (v3)
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Resolve conflict with Damien's FBC_CHIP_DEFAULT no fbc
reason.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since it will be used for the global bound/unbound list with full PPGTT,
this helps clarify things for upcoming code rework.
Recommended-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This makes it easier to catch leaks.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In some cases, we may not need GTT address space allocated to a stolen
object, so allow passing -1 to the preallocated function to indicate as
much.

v2: remove BUG_ON(gtt_offset & 4095) now that -1 is allowed (Ville)
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

But we need to get the right stolen base and make pre-allocated objects
for BIOS stuff so we don't clobber it.  If the BIOS hasn't allocated a
power context, we allocate one here too, from stolen space as required
by the docs.

v2: fix stolen to phys if ladder (Ben)
    keep BIOS reserved space out of allocator altogether (Ben)
v3: fix mask of stolen base (Ben)
v4: clean up preallocated object on unload (Ben)
    don't zero reg on unload (Jesse)
    fix mask harder (Jesse)
v5: use unref for freeing stolen bits (Chris)
    move alloc/free to intel_pm.c (Chris)
v6: NULL pctx at disable time so error paths work (Ben)
v7: use correct PCI device for config read (Jesse)
Reviewed-by: NBen Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Instead of repeatedly bombarding the user with a request to reboot and
increase the stolen size with every fb refresh, just inform them the
first time only.

v2: Rearrange code so the hint to increase the amount of memory stolen
by the BIOS is only emitted if we fail to find sufficient stolen memory
for FBC.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet: Fixup formatting code mismatch that gcc spotted.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Since for_each_sg_page supports already memory w/o backing pages we can
revert the corresponding workaround.

This reverts commit 5bd4687e.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Wrap a preallocated region of stolen memory within an ordinary GEM
object, for example the BIOS framebuffer.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is needed since currently sg_for_each_page assumes that we have
a valid page in each sg item. It is only a real problem for
CONFIG_SPARSEMEM where the page is dereferenced, in other cases the
iterator works ok with an invalid page pointer.

We can remove this workaround when we have fixed sg_page_iter to work on
scatterlists without backing pages.
Signed-off-by: NImre Deak <imre.deak@intel.com>

With the probe call in our dispatch table, we can now cut away the
last three remaining members in the intel_gtt shared struct and so
remove it completely.

v2: Rebased on top of Daniel's series
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: bikeshed commit message a bit.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We need to clean up the overlay first, before taking down the
stolen memory allocator.

This regression has been introducec in

commit 80405138
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Nov 15 11:32:29 2012 +0000

    drm/i915: Allocate overlay registers from stolen memory

v2: Rework the patch a bit as suggested by Chris Wilson:
- move the overlay teardown up, into the modeset cleanup
- move the stolen mm takedown into i915_gem_cleanup_stolen

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The primary purpose of this was to debug some use-after-free memory
corruption that was causing an OOPS inside drm/i915. As it turned out
the corruption was being caused elsewhere and i915.ko as a major user of
many objects was being hit hardest.

Indeed as we do frequent the generic kmalloc caches, dedicating one to
ourselves (or at least naming one for us depending upon the core) aids
debugging our own slab usage.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Allow for the creation of GEM objects backed by stolen memory. As these
are not backed by ordinary pages, we create a fake dma mapping and store
the address in the scatterlist rather than obj->pages.

v2: Mark _i915_gem_object_create_stolen() as static, as noticed by Jesse
Barnes.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>