In future patches, we will no longer be able to wait on a static global
seqno and instead have to break our wait up into phases. First we wait
for the global seqno assignment (upon submission to hardware), and once
submitted we wait for the hardware to complete.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-25-chris@chris-wilson.co.uk

Before suspend, we wait for the switch to the kernel context. In order
for all the other context images to be complete upon suspend, that
switch must be the last operation by the GPU (i.e. this idling request
must not overtake any pending requests). To make this request execute last,
we make it depend on every other inflight request.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-24-chris@chris-wilson.co.uk

Our timelines are more than just a seqno. They also provide an ordered
list of requests to be executed. Due to the restriction of handling
individual address spaces, we are limited to a timeline per address
space but we use a fence context per engine within.

Our first step to introducing independent timelines per context (i.e. to
allow each context to have a queue of requests to execute that have a
defined set of dependencies on other requests) is to provide a timeline
abstraction for the global execution queue.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-23-chris@chris-wilson.co.uk

After combining the dma-buf reservation object and the GEM reservation
object, we lost the ability to do a nonblocking wait on the i915 request
(as we blocked upon the reservation object during prepare_fb). We can
instead convert the reservation object into a fence upon which we can
asynchronously wait (including a forced timeout in case the DMA fence is
never signaled).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-22-chris@chris-wilson.co.uk

In preparation to support many distinct timelines, we need to expand the
activity tracking on the GEM object to handle more than just a request
per engine. We already use the struct reservation_object on the dma-buf
to handle many fence contexts, so integrating that into the GEM object
itself is the preferred solution. (For example, we can now share the same
reservation_object between every consumer/producer using this buffer and
skip the manual import/export via dma-buf.)

v2: Reimplement busy-ioctl (by walking the reservation object), postpone
the ABI change for another day. Similarly use the reservation object to
find the last_write request (if active and from i915) for choosing
display CS flips.

Caveats:

 * busy-ioctl: busy-ioctl only reports on the native fences, it will not
warn of stalls (in set-domain-ioctl, pread/pwrite etc) if the object is
being rendered to by external fences. It also will not report the same
busy state as wait-ioctl (or polling on the dma-buf) in the same
circumstances. On the plus side, it does retain reporting of which
*i915* engines are engaged with this object.

 * non-blocking atomic modesets take a step backwards as the wait for
render completion blocks the ioctl. This is fixed in a subsequent
patch to use a fence instead for awaiting on the rendering, see
"drm/i915: Restore nonblocking awaits for modesetting"

 * dynamic array manipulation for shared-fences in reservation is slower
than the previous lockless static assignment (e.g. gem_exec_lut_handle
runtime on ivb goes from 42s to 66s), mainly due to atomic operations
(maintaining the fence refcounts).

 * loss of object-level retirement callbacks, emulated by VMA retirement
tracking.

 * minor loss of object-level last activity information from debugfs,
could be replaced with per-vma information if desired
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-21-chris@chris-wilson.co.uk

Having moved the locked phase of freeing an object to a separate worker,
we can now declare to the core that we only need the unlocked variant of
driver->gem_free_object, and can use the simple unreference internally.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-20-chris@chris-wilson.co.uk

We want to hide the latency of releasing objects and their backing
storage from the submission, so we move the actual free to a worker.
This allows us to switch to struct_mutex freeing of the object in the
next patch.

Furthermore, if we know that the object we are dereferencing remains valid
for the duration of our access, we can forgo the usual synchronisation
barriers and atomic reference counting. To ensure this we defer freeing
an object til after an RCU grace period, such that any lookup of the
object within an RCU read critical section will remain valid until
after we exit that critical section. We also employ this delay for
rate-limiting the serialisation on reallocation - we have to slow down
object creation in order to prevent resource starvation (in particular,
files).

v2: Return early in i915_gem_tiling() ioctl to skip over superfluous
work on error.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-19-chris@chris-wilson.co.uk

As we can locklessly (well struct_mutex-lessly) acquire the backing
storage, do so in set-domain-ioctl to reduce the contention on the
struct_mutex.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-18-chris@chris-wilson.co.uk

We only need struct_mutex within pwrite for a brief window where we need
to serialise with rendering and control our cache domains. Elsewhere we
can rely on the backing storage being pinned, and forgive userspace any
races against us.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-17-chris@chris-wilson.co.uk

We only need struct_mutex within pread for a brief window where we need
to serialise with rendering and control our cache domains. Elsewhere we
can rely on the backing storage being pinned, and forgive userspace any
races against us.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-16-chris@chris-wilson.co.uk

Use the per-object mm.lock to allocate the backing storage (and hold a
reference to it across the dmabuf access) without resorting to
struct_mutex.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-15-chris@chris-wilson.co.uk

Break the allocation of the backing storage away from struct_mutex into
a per-object lock. This allows parallel page allocation, provided we can
do so outside of struct_mutex (i.e. set-domain-ioctl, pwrite, GTT
fault), i.e. before execbuf! The increased cost of the atomic counters
are hidden behind i915_vma_pin() for the typical case of execbuf, i.e.
as the object is typically bound between execbufs, the page_pin_count is
static. The cost will be felt around set-domain and pwrite, but offset
by the improvement from reduced struct_mutex contention.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-14-chris@chris-wilson.co.uk

The plan is to move obj->pages out from under the struct_mutex into its
own per-object lock. We need to prune any assumption of the struct_mutex
from the get_pages/put_pages backends, and to make it easier we pass
around the sg_table to operate on rather than indirectly via the obj.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-13-chris@chris-wilson.co.uk

The plan is to make obtaining the backing storage for the object avoid
struct_mutex (i.e. use its own locking). The first step is to update the
API so that normal users only call pin/unpin whilst working on the
backing storage.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-12-chris@chris-wilson.co.uk

We can use the radixtree index of the obj->pages to find the start
position of the desired partial range.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-11-chris@chris-wilson.co.uk

A while ago we switched from a contiguous array of pages into an sglist,
for that was both more convenient for mapping to hardware and avoided
the requirement for a vmalloc array of pages on every object. However,
certain GEM API calls (like pwrite, pread as well as performing
relocations) do desire access to individual struct pages. A quick hack
was to introduce a cache of the last access such that finding the
following page was quick - this works so long as the caller desired
sequential access. Walking backwards, or multiple callers, still hits a
slow linear search for each page. One solution is to store each
successful lookup in a radix tree.

v2: Rewrite building the radixtree for clarity, hopefully.

v3: Rearrange execbuf to avoid calling i915_gem_object_get_sg() from
within an atomic section and so relax the allocation context to a simple
GFP_KERNEL and mutex.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-10-chris@chris-wilson.co.uk

Add lockdep_assert_held(struct_mutex) to the API preamble of the
internal GEM interfaces.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-9-chris@chris-wilson.co.uk

The golden render state is constant, but we recreate the batch setting
it up for every new context. If we keep that batch in a volatile cache
we can safely reuse it whenever we need to initialise a new context. We
mark the pages as purgeable and use the shrinker to recover pages from
the batch whenever we face memory pressues, recreating that batch afresh
on the next new context.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtien@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-8-chris@chris-wilson.co.uk

Quite a few of our objects used for internal hardware programming do not
benefit from being swappable or from being zero initialised. As such
they do not benefit from using a shmemfs backing storage and since they
are internal and never directly exposed to the user, we do not need to
worry about providing a filp. For these we can use an
drm_i915_gem_object wrapper around a sg_table of plain struct page. They
are not swap backed and not automatically pinned. If they are reaped
by the shrinker, the pages are released and the contents discarded. For
the internal use case, this is fine as for example, ringbuffers are
pinned from being written by a request to be read by the hardware. Once
they are idle, they can be discarded entirely. As such they are a good
match for execlist ringbuffers and a small variety of other internal
objects.

In the first iteration, this is limited to the scratch batch buffers we
use (for command parsing and state initialisation).

v2: Allocate physically contiguous pages, where possible.
v3: Reduce maximum order on subsequent requests following an allocation
failure.
v4: Fix up mismatch between swiotlb segment size and page count (it
counts in 2k units, not 4k pages)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-7-chris@chris-wilson.co.uk

We only need the active reference to keep the object alive after the
handle has been deleted (so as to prevent a synchronous gem_close). Why
then pay the price of a kref on every execbuf when we can insert that
final active ref just in time for the handle deletion?
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-6-chris@chris-wilson.co.uk

Since we only use the more generic unlocked variant, just rename it as
the normal i915_gem_active_wait(). The temporary cost is that we need to
always acquire the reference in a RCU safe manner, but the benefit is
that we will combine the common paths.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-5-chris@chris-wilson.co.uk

Our low-level wait routine has evolved from our generic wait interface
that handled unlocked, RPS boosting, waits with time tracking. If we
push our GEM fence tracking to use reservation_objects (required for
handling multiple timelines), we lose the ability to pass the required
information down to i915_wait_request(). However, if we push the extra
functionality from i915_wait_request() to the individual callsites
(i915_gem_object_wait_rendering and i915_gem_wait_ioctl) that make use
of those extras, we can both simplify our low level wait and prepare for
extending the GEM interface for use of reservation_objects.

v2: Rewrite i915_wait_request() kerneldocs
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-4-chris@chris-wilson.co.uk

The throttle-ioctl never touches the struct_mutex. It does, however, as
part of its ABI report whether the hardware is terminally wedged. For
that purposes, it only has to report the current state and not incur the
cost of checking/waiting every invocation, as we do not have to wait for
a reset before waiting on a request to ensure completion (that is baked
into the wait request implementation).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-3-chris@chris-wilson.co.uk

In forthcoming patches, we want to be able to dynamically allocate the
wait_queue_t used whilst awaiting. This is more convenient if we extend
the i915_sw_fence_await_sw_fence() to perform the allocation for us if
we pass in a gfp mask as an alternative than a preallocated struct.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-2-chris@chris-wilson.co.uk

We will need to wait on DMA completion (as signaled via struct fence)
before executing our i915_gem_request. Therefore we want to expose a
method for adding the await on the fence itself to the request.

v2: Add a comment detailing a failure to handle a signal-on-any
fence-array.
v3: Pretend that magic numbers don't exist.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-1-chris@chris-wilson.co.uk

We are not allowed to touch the GTT entries underneath an atomic section,
as they take a rpm wakelock (which is illegal from atomic context) and
in the near future acquiring the DMA address for a page within an object
may sleep for an allocation. This makes the current shortcircuit in
relocation_iomap() for performing a second relocation on an adjacent page
illegal, and we need to release the atomic iomapping, lookup the DMA,
insert it into the GTT before reentering the atomic iomap section.

As it happens, this is precisely what we do on if we are using an
iomapping over the full object and not just a single page and by
removing the shortcut, we do the right thing.

Fixes: 9c870d03 ("drm/i915: Use RPM as the barrier for controlling...")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028142756.3850-1-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

This was the only use of (misleadingly-named) intel_num_planes()
function, so we can remove it as well.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477522291-10874-3-git-send-email-matthew.d.roper@intel.comReviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>

This macro's name is a bit misleading; it doesn't actually iterate over
all planes since it omits the cursor plane.  Its only uses are in gen9
code which is using it to iterate over the universal planes (which we
treat as primary+sprites); in these cases the legacy cursor registers
are programmed independently if necessary.  The macro's iterator value
(0 for primary plane, spritenum+1 for each secondary plane) also isn't
meaningful outside the gen9 context where the hardware considers them to
all be "universal" planes that follow this numbering.

This is just a renaming/clarification patch with no functional change.
However it will make the subsequent patches more clear.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477522291-10874-2-git-send-email-matthew.d.roper@intel.comReviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>

These static helper functions are required to be used during
fallback link rate implemnetation so they need to be placed at the top
of the file.

v3:
* Add cleanup to other patch (Mika Kahola)
v2:
* Dont move around functions declared in intel_drv.h (Rodrigo Vivi)

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: NMika Kahola <mika.kahola@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477524358-16563-4-git-send-email-manasi.d.navare@intel.com

The port registers related to the phys in broxton map to different
channels and specific phys. Make that mapping explicit.

v2: Pass enum dpio_phy to macros instead of mmio base. (Imre)

v3: Fix typo in macros. (Imre)

v4: Also change variables from u32 to enum dpio_phy. (Imre)
    Remove leftovers from previous version. (Imre)

v5: Actually git add the changes.
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1476863940-6019-1-git-send-email-ander.conselvan.de.oliveira@intel.com

Use struct bxt_ddi_phy_info to hold information of where the Rcomp
resistor is located, instead of hard coding it in the init sequence.

Note that this moves the enabling of the phy with the Rcomp resistor out
of the power well enable code. That should be safe since
bxt_ddi_phy_init() is called while the power domains lock is held, and
that is the only way that function gets called, so there is no
possibility of a concurrent phy enable caused by a power domain get
call.

v2: Replace comment about lock with lockdep_assert_held()  (Imre)
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/62d209950ad48484564f3e793cf247cf62572a39.1475770848.git-series.ander.conselvan.de.oliveira@intel.com

Information about which phy is dual channel is hardcoded in the phy init
sequence. Split that to a separate struct so the init sequence is more
generic.

v2: Restore mangled part that ended up in following patch. (Imre)
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/9102f4c984044126057e4fdd1b91a615ff25fae6.1475770848.git-series.ander.conselvan.de.oliveira@intel.com

The vswing sequence is related to the DPIO phy, so move it closer to the
rest of DPIO phy related code.
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/59aa5c85a115c5cbed81e793f20cd7b9f8de694b.1475770848.git-series.ander.conselvan.de.oliveira@intel.com

Move the DPIO phy documentation section to intel_dpio_phy.c, since that
is a more suitable place now that there is a source file dedicated for
those phys.
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/55a2d38c15c06a8c5bce498b28decc03948f0224.1475770848.git-series.ander.conselvan.de.oliveira@intel.com

The phy in broxton is also a dpio phy, similar to cherryview but with
programming through MMIO. So move the code together with the other
similar phys.
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/d611de6d256593cf904172db7ff27f164480c228.1475770848.git-series.ander.conselvan.de.oliveira@intel.com

Pass lane count to bxt_ddi_phy_calc_lane_optmin_mask() instead of having
it extract that number from a pipe_config to decouple the phy code from
intel_crtc_state.
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/a4977e0207e594953c4f9d1b5f2ef972a8679e74.1475770848.git-series.ander.conselvan.de.oliveira@intel.com

The mapping from the BXT_DPIO_CMN_* power wells to their respective phys
required a detour implemented in the bxt_power_well_to_phy() function.
Instead, embed that information directly into the power_well struct, by
resurrecting the data field.
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/7fe97582fa08c7340ce6a3b6b0ea3e72a73182d7.1475770848.git-series.ander.conselvan.de.oliveira@intel.com

Calling it data seems to imply arbitrary data can be associated with the
power well. However, that field is used for look ups and expected to be
unique, so rename it.
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/f3916c3c5bfa793b0fc870fd44007a3ff425194d.1475770848.git-series.ander.conselvan.de.oliveira@intel.com

Signed-off-by: NRex Zhu <Rex.Zhu@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

v2: move return value check as well
Signed-off-by: NRex Zhu <Rex.Zhu@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>