If we change the wait_queue_t from using the autoremove_wake_function to
the default_wake_function, we no longer have to restore the wait_queue_t
entry on the wait_queue_head_t list after being woken up by it, as we
are unusual in sleeping multiple times on the same wait_queue_t.
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/20170223074422.4125-14-chris@chris-wilson.co.uk

Add a mock selftest to preempt a request and check that we cancel it,
requeue the request and then complete its execution.

v2: Error leaks no more.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223074422.4125-13-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

After the request is cancelled, we then need to remove it from the
global execution timeline and return it to the context timeline, the
inverse of submit_request().

v2: Move manipulation of struct intel_wait to helpers
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223074422.4125-12-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

If we preempt a request and remove it from the execution queue, we need
to undo its global seqno and restart any waiters.
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/20170223074422.4125-11-chris@chris-wilson.co.uk

The plan in the near-future is to allow requests to be removed from the
signaler. We can no longer then rely on holding a reference to the
request for the duration it is in the signaling tree, and instead must
obtain a reference to the request for the current operation using RCU.
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/20170223074422.4125-10-chris@chris-wilson.co.uk

A request is assigned a global seqno only when it is on the hardware
execution queue. The global seqno can be used to maintain a list of
requests on the same engine in retirement order, for example for
constructing a priority queue for waiting. Prior to its execution, or
if it is subsequently removed in the event of preemption, its global
seqno is zero. As both insertion and removal from the execution queue
may operate in IRQ context, it is not guarded by the usual struct_mutex
BKL. Instead those relying on the global seqno must be prepared for its
value to change between reads. Only when the request is complete can
the global seqno be stable (due to the memory barriers on submitting
the commands to the hardware to write the breadcrumb, if the HWS shows
that it has passed the global seqno and the global seqno is unchanged
after the read, it is indeed complete).
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/20170223074422.4125-9-chris@chris-wilson.co.uk

On reflection, we are only using the execute fence as a waitqueue on the
global_seqno and not using it for dependency tracking between fences
(unlike the submit and dma fences). By only treating it as a waitqueue,
we can then treat it similar to the other waitqueues during submit,
making the code simpler.
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/20170223074422.4125-8-chris@chris-wilson.co.uk

It had only one callsite and existed to keep the code clearer. Now
having shared the wait-on-error between phases and with plans to change
the wait-for-execute in the next few patches, remove the out of line
wait loop and move it into the main body of i915_wait_request.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223074422.4125-7-chris@chris-wilson.co.uk

Add ourselves to the gpu error waitqueue earlier on, even before we
determine we have to wait on the seqno. This is so that we can then
share the waitqueue between stages in subsequent patches.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223074422.4125-6-chris@chris-wilson.co.uk

Use a local variable to avoid having to type out the full name of the
gpu_error wait_queue.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223074422.4125-5-chris@chris-wilson.co.uk

Move the companion functions next to each other.
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/20170223074422.4125-4-chris@chris-wilson.co.uk

Replace the global device seqno with one for each engine, and account
for in-flight seqno on each separately. This is consistent with
dma-fence as each timeline has separate fence-contexts for each engine
and a seqno is only ordered within a fence-context (i.e.  seqno do not
need to be ordered wrt to other engines, just ordered within a single
engine). This is required to enable request rewinding for preemption on
individual engines (we have to rewind the global seqno to avoid
overflow, and we do not have to rewind all engines just to preempt one.)

v2: Rename active_seqno to inflight_seqnos to more clearly indicate that
it is a counter and not equivalent to the existing seqno. Update
functions that operated on active_seqno similarly.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223074422.4125-3-chris@chris-wilson.co.uk

When dma_fence_signal() is called, it sets a flag to indicate the fence
is complete. Before the dma_fence is signaled, the seqno check will
first be passed. During an unlocked check (such as inside a waiter), it
is possible for the fence to be signaled even though the seqno has been
reset (by engine wraparound). In this case the waiter will be kicked,
but for an extra layer of protection we can check the persistent
signaled bit from the fence.
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/20170223074422.4125-2-chris@chris-wilson.co.uk

This reverts commit 7ee68603 "drm/i915/dp: Ratelimit DP aux timeout
messages" as although it successfully squelches the debug messages, when
it does so it generates a warning instead. CI lights up orange with all
the warnings!

In its current incarnation DRM_DEBUG_RATELIMITED is not usable for us,
and we need to first teach lib/ratelimit.c not to warn when used for
debug messages.

Fixes: 7ee68603 ("drm/i915/dp: Ratelimit DP aux timeout messages")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Lyude <lyude@redhat.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Link: http://patchwork.freedesktop.org/patch/msgid/20170223115102.7059-1-chris@chris-wilson.co.ukAcked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

Geminilake scalers can do 7x7 filtering for all supported input sizes,
so it doesn't need the "high quality" mode programming, which was
actually removed from that platform.

v2: Split dev_priv parameter change out. (Ville)
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>,
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223071600.14356-5-ander.conselvan.de.oliveira@intel.com

Pass dev_priv to intel_atomic_setup_scalers(). The next patch will need
a dev_priv pointer.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223071600.14356-4-ander.conselvan.de.oliveira@intel.com

Geminilake can output two pixels per clock, and that affects the maximum
scaling factor for its scalers. Take that into account and avoid the
following warning:

WARNING: CPU: 1 PID: 593 at drivers/gpu/drm/i915/intel_display.c:13223 skl_max_scale.part.129+0x78/0x80 [i915]
WARN_ON_ONCE(!crtc_clock || cdclk < crtc_clock)
Modules linked in: x86_pkg_temp_thermal i915 coretemp kvm_intel kvm i2c_algo_bit drm_kms_helper irqbypass crct10dif_pclmul prime_numbers crc32_pclmul drm ghash_clmulni_intel shpchp tpm_tis tpm_tis_core tpm nfsd authw
CPU: 1 PID: 593 Comm: kworker/u8:3 Tainted: G        W       4.10.0-rc8ander+ #330
Hardware name: Intel Corp. Geminilake/GLK RVP1 DDR4 (05), BIOS GELKRVPA.X64.0035.B33.1702150552 02/15/2017
Workqueue: events_unbound async_run_entry_fn
Call Trace:
 dump_stack+0x86/0xc3
 __warn+0xcb/0xf0
 warn_slowpath_fmt+0x5f/0x80
 skl_max_scale.part.129+0x78/0x80 [i915]
 intel_check_primary_plane+0xa6/0xc0 [i915]
 intel_plane_atomic_check_with_state+0xd1/0x1a0 [i915]
 ? drm_printk+0xb5/0xc0 [drm]
 intel_plane_atomic_check+0x3d/0x80 [i915]
 drm_atomic_helper_check_planes+0x7c/0x200 [drm_kms_helper]
 intel_atomic_check+0xa5b/0x11a0 [i915]
 drm_atomic_check_only+0x353/0x600 [drm]
 ? drm_atomic_add_affected_connectors+0x10c/0x120 [drm]
 drm_atomic_commit+0x18/0x50 [drm]
 restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
 drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
 drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
 intel_fbdev_set_par+0x1a/0x70 [i915]
 fbcon_init+0x582/0x610
 visual_init+0xd6/0x130
 do_bind_con_driver+0x1da/0x3c0
 do_take_over_console+0x116/0x180
 do_fbcon_takeover+0x5c/0xb0
 fbcon_event_notify+0x772/0x8a0
 ? __blocking_notifier_call_chain+0x35/0x70
 notifier_call_chain+0x4a/0x70
 __blocking_notifier_call_chain+0x4d/0x70
 blocking_notifier_call_chain+0x16/0x20
 fb_notifier_call_chain+0x1b/0x20
 register_framebuffer+0x278/0x360
 drm_fb_helper_initial_config+0x253/0x440 [drm_kms_helper]
 intel_fbdev_initial_config+0x18/0x30 [i915]
 async_run_entry_fn+0x39/0x170
 process_one_work+0x212/0x670
 ? process_one_work+0x197/0x670
 worker_thread+0x4e/0x490
 kthread+0x101/0x140
 ? process_one_work+0x670/0x670
 ? kthread_create_on_node+0x60/0x60
 ret_from_fork+0x31/0x40

v2: s/max_pixclk/max_dotclk/ (Ville)
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223071600.14356-3-ander.conselvan.de.oliveira@intel.com

Geminilake has a third sprite plane (or fourth universal plane) that is
independent from the cursor. Make sure that for_each_plane_id_on_crtc()
is aware of that extra plane so that the watermark code takes it into
account.

Fixes: e9c98825 ("drm/i915/glk: Configure number of sprite planes properly")
Cc: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <drm-intel-fixes@lists.freedesktop.org>
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223071600.14356-2-ander.conselvan.de.oliveira@intel.com

Testing with concurrent GGTT accesses no longer show the coherency
problems from yonder, commit 5bab6f60 ("drm/i915: Serialise updates
to GGTT with access through GGTT on Braswell"). My presumption is that
the root cause was more likely fixed by commit 3b5724d7 ("drm/i915:
Wait for writes through the GTT to land before reading back"), along
with the use of WC updates to the global gTT in commit 8448661d
("drm/i915: Convert clflushed pagetables over to WC maps". Given
that the original symptoms can no longer be reproduced, time to remove
the workaround.

Testcase: igt/gem_concurrent_blit
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170220124718.14796-1-chris@chris-wilson.co.ukReviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Right now this is just leaving a lot of spam in dmesg that makes real
issues more difficult to debug. As well (as noted by the comment right
above the DRM_DEBUG_KMS() call) this is normal behavior when there's
nothing connected to the DisplayPort connector.
Signed-off-by: NLyude <lyude@redhat.com>

Setting retire=true is identical to using origin=ORIGIN_CS, so make the
same simplification to intel_fb_obj_flush() as already employed for
intel_fb_obj_invalidate().
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/20170222114049.28456-6-chris@chris-wilson.co.uk

Flushing the cachelines for an object is slow, can be as much as 100ms
for a large framebuffer. We currently do this under the struct_mutex BKL
on execution or on pageflip. But now with the ability to add fences to
obj->resv for both flips and execbuf (and we naturally wait on the fence
before CPU access), we can move the clflush operation to a workqueue and
signal a fence for completion, thereby doing the work asynchronously and
not blocking the driver or its clients.

v2: Introduce i915_gem_clflush.h and use a new name, split out some
extras into separate patches.
Suggested-by: NAkash Goel <akash.goel@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170222114049.28456-5-chris@chris-wilson.co.uk

Generalise the skip for physical and stolen objects by skipping anything
we do not have a valid address for inside the sg.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170222114049.28456-4-chris@chris-wilson.co.uk

We have three different paths by which userspace wants to flush the
display plane (i.e. objects with obj->pin_display). Use a common helper
to identify those paths and to simplify a later change.

v2: Include the conditional in the name, i915_gem_object_flush_if_display
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/20170222114049.28456-3-chris@chris-wilson.co.uk

For use in the next patch, take the current is-coherent helper and add
it to i915_gem_object.h
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/20170222114049.28456-2-chris@chris-wilson.co.uk

The change_domain tracepoint has been inaccurate for a few years - it
doesn't fully capture the domains, especially with userspace bypassing
them. It is defunct, misleading and time to be removed.
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/20170222114049.28456-1-chris@chris-wilson.co.uk

Handling the dynamic charp module parameter requires us to copy it for
the error state, or remember to lock it when reading (in case it used
with 0600).

v2: Use __always_inline and __builtin_strcmp
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/20170221162619.15954-1-chris@chris-wilson.co.ukReviewed-by: NJani Nikula <jani.nikula@intel.com>

When not using GuC submission, the ring buffer size for GVT context is
512KB which is the max size. When switching to GuC submission, the ring
buffer size is required to be less than 16KB. So use the GVT context
default ring buffer size if GuC submission is enabled.
Signed-off-by: NChuanxiao Dong <chuanxiao.dong@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170216063639.GA17107@intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

It is useful to provide this info to match the one provided
in the request tracepoints.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170221091350.14605-1-tvrtko.ursulin@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Two new tracepoints placed at the call sites where requests are
actually passed to the GPU enable userspace to track engine
utilisation.

These tracepoints are only enabled when the
DRM_I915_LOW_LEVEL_TRACEPOINTS Kconfig option is enabled.

v2: Fix compilation with !CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS.

v3: Name global seqno consistently across tracepoints.

v4: Remove port info from request out tracepoint. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

i915_gem_ring_notify is more appropriate since we do not have
the request information at this point, but it is simply a
signal from the engine that some request has been completed.

v2:
  * Always trace and log if there were any waiters.
  * Rename to intel_engine_notify. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

These new tracepoints are emitted once the request is ready to
be submitted to the GPU and once the request is about to
be submitted to the GPU, respectively.

Former condition triggers as soon as all the fences and
dependencies have been resolved, and the latter once the
backend is about to submit it to the GPU.

New tracepoint are enabled via the new
DRM_I915_LOW_LEVEL_TRACEPOINTS Kconfig option which is disabled
by default to alleviate the performance impact concerns.

v2: Move execute tracepoint to __i915_gem_request_submit.
    (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Tracepoint is not used and won't be suitable for its replacement.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Provide the same information as the other request event classes.

v2: Pass in flags so we can properly report the blocking status.
    (Chris Wilson)

v3: Log hex with 0x prefix for clarity.

v4: Derive blocking status from flags. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Rename it to i915_gem_request_queue and fix the logged info
equivalent to the i915_gem_request even class. Also moved it
a bit further apart from the i915_gem_request_add tracepoint
since they otherwise provide similar information too close in
time.

v2: Remove sw fence singalling. We will rely on the soon to
    come GuC scheduling backend to enable that. (Chris Wilson)

v3: Log hex with 0x prefix for clarity.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

At the moment only the global seqno is logged which is not set
until the request is ready for submission.

Add the per-contex seqno and the context hardware id which are
both interesting data points.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Compact the name of the macro and reg_state variable, and cache
some data in local variables to make the function more compact
and more readable.

v2: Fixup some checkpatch warnings.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170221095839.30525-1-tvrtko.ursulin@linux.intel.com

Replace the calls to ww_mutex_lock(&resv->lock) with the helper
reservation_object_lock(resv) and similarly for unlock.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170221091723.6219-1-chris@chris-wilson.co.ukReviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

The hardware requires that the tail pointer only advance in qword units,
so assert that the value we write is aligned to qwords, and similarly
enforce this restriction onto the request->tail.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170217163833.731-1-chris@chris-wilson.co.ukReviewed-by: NMichał Winiarski <michal.winiarski@intel.com>

Verify that the refcount of all power wells match their HW enabled
state at the end of modeset HW state readout.

Also add documentation on how the reference count for each power well is
supposed to be acquired during initialization and HW state readout.

Suggested by Ander.

Cc: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Cc: David Weinehall <david.weinehall@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NAnder Conselvan de Oliveira <conselvan2@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1487345986-26511-6-git-send-email-imre.deak@intel.com