Introduce an generic API to reset vGPU virtual submission interface.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

Introduce vGPU submission ops to support easy switching submission mode
of one vGPU between different OSes.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

Move common vGPU workload creation functions into scheduler.c since
they are not specific to execlist emulation.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

Move common workload preparation into prepare_workload() in scheduler.c,
as they are not specific to execlist emulation.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

Factor out prepare_workload() for the following re-factor.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

Factor out vGPU workload creation/destroy functions since they are not
specific to execlist emulation.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

When a scan error occurs in dispatch_workload, this patch is to
check the healthy state and free all the queued workloads before
the failsafe mode is entered.
Signed-off-by: Nfred gao <fred.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Generally, there are 3 types of errors during command scan: a) some
commands might be unknown with EBADRQC;  b) some cmd access invalid
address with EFAULT; c) some unexpected force nonpriv cmd with EPERM.
later the healthy state can be judged through the return error.

v2:
- remove some internal i915 errors rating.  (Zhenyu)

v3:
- the healthy state is judged through the internal defined return
  error. (Zhenyu)
- force non priv cmd error can be ignored. (Kevin)

v4:
- reuse standard defined errno instead of recreate, e.g EBADRQC for
  unknown cmd, EFAULT for invalid address, EPERM for nonpriv. (Zhenyu)

v5:
- remove some irrelevant code for the patch.
- fix typo of vgpu_is_vm_unhealthy. (Zhenyu)

v6:
- move the healthy check and failsafe code into another patch. (Zhenyu)

v7:
- polish title and commit message. (Zhenyu)
Signed-off-by: Nfred gao <fred.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Move tlb_handle_pending into intel_vgpu_submssion since it belongs to a
part of vGPU submission stuffs
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

Introduce intel_vgpu_submission to hold all members related to submission
in struct intel_vgpu before.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

Move vGPU workload cache initialization/de-initialization into
intel_vgpu_{setup, clean}_submission() since they are not specific to
execlist stuffs.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

To move workload related functions into scheduler.c, an expected way is
to collect all the init/clean functions related to vGPU workload
submission into fewer functions.

Rename intel_vgpu_{init, clean}_gvt_context() for above usage in future.
Signed-off-by: NZhi Wang <zhi.a.wang@intel.com>

Take a copy of the HW state after a reset upon module loading by
executing a context switch from a blank context to the kernel context,
thus saving the default hw state over the blank context image.
We can then use the default hw state to initialise any future context,
ensuring that each starts with the default view of hw state.

v2: Unmap our default state from the GTT after stealing it from the
context. This should stop us from accidentally overwriting it via the
GTT (and frees up some precious GTT space).

Testcase: igt/gem_ctx_isolation
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171110142634.10551-7-chris@chris-wilson.co.uk

Let the listener know that the context we just scheduled out was not
complete, and will be scheduled back in at a later point.

v2: Handle CONTEXT_STATUS_PREEMPTED in gvt by aliasing it to
CONTEXT_STATUS_OUT for the moment, gvt can expand upon the difference
later.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: "Zhenyu Wang" <zhenyuw@linux.intel.com>
Cc: "Wang, Zhi A" <zhi.a.wang@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003203453.15692-3-chris@chris-wilson.co.uk

Not only the context image consist of two parts (the PPHWSP, and the
logical context state), but we also allocate a header at the start of
for sharing data with GuC. Thus every lrc looks like this:

  | [guc]          | [hwsp] [logical state] |
  |<- our header ->|<- context image      ->|

So far, we have oversimplified whenever we use each of these parts of the
context, just because the GuC header happens to be in page 0, and the
(PP)HWSP is in page 1. But this had led to using the same define for more
than one meaning (as a page index in the lrc and as 1 page).

This patch adds defines for the GuC shared page, the PPHWSP page and the
start of the logical state. It also updated the places where the old
define was being used. Since we are not changing the size (or format) of
the context, there are no functional changes.

v2: Use PPHWSP index for hws again.
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: intel-gvt-dev@lists.freedesktop.org
Link: http://patchwork.freedesktop.org/patch/msgid/20170712193032.27080-1-michel.thierry@intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20170913085605.18299-1-chris@chris-wilson.co.uk

When an error occurs in dispatch_workload, this patch is to do the
proper cleanup and rollback to the original states before the workload
is abandoned.

v2:
- split the mixed several error paths for better review. (Zhenyu)

v3:
- original PTR_ERR(cs) is good and code cleanup. (Zhenyu)

v4:
- reuse the existing i915_add_request for error handling. (Zhenyu)

v5:
- remove the duplicate error handling release_shadow_wa_ctx and
  move the engine->context_unpin upper. (Zhenyu)

v6:
- keep the old label "out". (Zhenyu)
Signed-off-by: Nfred gao <fred.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

When an error occurs after shadow_indirect_ctx, this patch is to do the
proper cleanup and rollback to the original states for shadowed indirect
context before the workload is abandoned.

v2:
- split the mixed several error paths for better review. (Zhenyu)

v3:
- no return check for clean up functions. (Changbin)

v4:
- expose and reuse the existing release_shadow_wa_ctx. (Zhenyu)

v5:
- move the release function to scheduler.c file. (Zhenyu)

v6:
- move error handling code of intel_gvt_scan_and_shadow_workload
  to here. (Zhenyu)
Signed-off-by: Nfred gao <fred.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Currently i915 request structure and shadow ring buffer are allocated
before command scan, so it will have to restore to previous states once
any error happens afterwards in the long dispatch_workload path.

This patch is to introduce a reserved ring buffer created at the beginning
of vGPU initialization. Workload will be coped to this reserved buffer and
be scanned first, the i915 request and shadow ring buffer are only
allocated after the result of scan is successful.

To balance the memory usage and buffer alloc time, the coming bigger ring
buffer will be reallocated and kept until more bigger buffer is coming.

v2:
- use kmalloc for the smaller ring buffer, realloc if required. (Zhenyu)

v3:
- remove the dynamically allocated ring buffer. (Zhenyu)

v4:
- code style polish.
- kfree previous allocated buffer once kmalloc failed. (Zhenyu)
Signed-off-by: Nfred gao <fred.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

The current context logic only updates the descriptor of context when
it's being pinned to graphics memory space. But this cannot satisfy the
requirement of shadow context. The addressing mode of the pinned shadow
context descriptor may be changed according to the guest addressing mode.
And this won't be updated, as the already pinned shadow context has no
chance to update its descriptor. And this will lead to GPU hang issue,
as shadow context is used with wrong descriptor. This patch fixes this
issue by letting the pinned shadow context descriptor update its
addressing mode on demand.

This patch fixes GPU HANG issue which happends after changing the
grub parameter i915.enable_ppgtt form 0x01 to 0x03 or vice versa and
then rebooting the guest.
Signed-off-by: NTina Zhang <tina.zhang@intel.com>
Signed-off-by: NKechen Lu <kechen.lu@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

The function workload scan and shadow have to hold the drm.struct_mutex
before called. To avoid misusing of this function, add a lockdep assert
in it.
Signed-off-by: NPing Gao <ping.a.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Let the workload audit and shadow ahead of vGPU scheduling, that
will eliminate GPU idle time and improve performance for multi-VM.

The performance of Heaven running simultaneously in 3VMs has
improved 20% after this patch.

v2:Remove condition current->vgpu==vgpu when shadow during ELSP
writing.
Signed-off-by: NPing Gao <ping.a.gao@intel.com>
Reviewed-by: NZhi Wang <zhi.a.wang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

To perform the workload scan and shadow in ELSP writing stage for
performance consideration, the workload scan and shadow stuffs
should be factored out from dispatch_workload().

v2:Put context pin before i915_add_request;
   Refine the comments;
   Rename some APIs;

v3:workload->status should set only when error happens.
v4:i915_add_request is must to have after i915_gem_request_alloc.
Signed-off-by: NPing Gao <ping.a.gao@intel.com>
Reviewed-by: NZhi Wang <zhi.a.wang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Use resetting_eng to identify which engine is resetting
so the rest ones' workload won't be impacted

v2:
- use ENGINE_MASK(ring_id) instead of (1 << ring_id). (Zhenyu)
Signed-off-by: NChuanxiao Dong <chuanxiao.dong@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

The req->fence.error will be set if this request caused GPU hang so
we can use this value to workload->status to indicate whether this
GVT request caused any problem. If it caused GPU hang, we shouldn't
trigger any context switch back to the guest.

v2:
- only take -EIO from fence->error. (Zhenyu)

Fixes: 8f1117ab (drm/i915/gvt: handle workload lifecycle properly)
Signed-off-by: NChuanxiao Dong <chuanxiao.dong@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

For the vGPU workloads, now GVT-g use per vGPU scheduler, the per-ring
work_thread only pick workload belongs to the current vGPU. And with time
slice based scheduler, it waits all the engines become idle before do vGPU
switch. So we can run free dispatch in per-ring work_thread, different ring
running in different 'vGPU' won't happen.

For the workloads between vGPU and Host, this scheduler_mutex can't block
host to dispatch workload into other ring engines.

Here remove this mutex since it impacts the performance when applications
use more than 1 ring engines in 1 vgpu.

ring0 running in vGPU1, ring1 running in Host. Will happen.
ring0 running in vGPU1, ring1 running in vGPU2. Won't happen.
Signed-off-by: NWeinan Li <weinan.z.li@intel.com>
Signed-off-by: NPing Gao <ping.a.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

If we move the actual cleanup of the context to a worker, we can allow
the final free to be called from any context and avoid undue latency in
the caller.

v2: Negotiate handling the delayed contexts free by flushing the
workqueue before calling i915_gem_context_fini() and performing the final
free of the kernel context directly
v3: Flush deferred frees before new context allocations
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/20170620110547.15947-2-chris@chris-wilson.co.uk

The time based scheduler poll context busy status at every
micro-second during vGPU switch, it will make GPU idle for a while
when the context is very small and completed before the next
micro-second arrival. Trigger scheduling immediately after context
complete will eliminate GPU idle and improve performance.

Create two vGPU with same type, run Heaven simultaneously:
Before this patch:
 +---------+----------+----------+
 |         |  vGPU1   |   vGPU2  |
 +---------+----------+----------+
 |  Heaven |  357     |    354   |
 +-------------------------------+

After this patch:
 +---------+----------+----------+
 |         |  vGPU1   |   vGPU2  |
 +---------+----------+----------+
 |  Heaven |  397     |    398   |
 +-------------------------------+

v2: Let need_reschedule protect by gvt-lock.
Signed-off-by: NPing Gao <ping.a.gao@intel.com>
Signed-off-by: NWeinan Li <weinan.z.li@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Commit ab9da627906a ("drm/i915: make context status notifier head be
per engine") gives us a chance to inspect every single request. Then
we can eliminate unnecessary mmio switching for same vGPU. We only
need mmio switching for different VMs (including host).

This patch introduced a new general API intel_gvt_switch_mmio() to
replace the old intel_gvt_load/restore_render_mmio(). This function
can be further optimized for vGPU to vGPU switching.

To support individual ring switch, we track the owner who occupy
each ring. When another VM or host request a ring we do the mmio
context switching. Otherwise no need to switch the ring.

This optimization is very useful if only one guest has plenty of
workloads and the host is mostly idle. The best case is no mmio
switching will happen.

v2:
  o fix missing ring switch issue. (chuanxiao)
  o support individual ring switch.
Signed-off-by: NChangbin Du <changbin.du@intel.com>
Reviewed-by: NChuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Since unifying ringbuffer/execlist submission to use
engine->pin_context, we ensure that the intel_ring is available before
we start constructing the request. We can therefore move the assignment
of the request->ring to the central i915_gem_request_alloc() and not
require it in every engine->request_alloc() callback. Another small step
towards simplification (of the core, but at a cost of handling error
pointers in less important callers of engine->pin_context).

v2: Rearrange a few branches to reduce impact of PTR_ERR() on gcc's code
generation.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NOscar Mateo <oscar.mateo@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170504093308.4137-1-chris@chris-wilson.co.uk

Pre-calculate engine context size based on engine class and device
generation and store it in the engine instance.

v2:
- Squash and get rid of hw_context_size (Chris)

v3:
- Move after MMIO init for probing on Gen7 and 8 (Chris)
- Retained rounding (Tvrtko)
v4:
- Rebase for deferred legacy context allocation
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: intel-gvt-dev@lists.freedesktop.org
Acked-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

As those debug messages might appear in every timer call for scheduler,
it's too noisy, eat too much log and aren't meaningful. So remove them.

Cc: Ping Gao <ping.a.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Extend function dispatch logic to support KBL platform.
Signed-off-by: NXu Han <xu.han@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

In my previous Commit ab9da627906a ("drm/i915: make context status
notifier head be per engine") rely on scheduler->current_workload[x]
to distinguish gvt spacial request from i915 request. But this is
not always true since no synchronization between workload_thread and
lrc irq handler.

    lrc irq handler               workload_thread
         ----                          ----
  pick i915 requests;
                                intel_vgpu_submit_execlist();
                                current_workload[x] = xxx;
  shadow_context_status_change();

Then current_workload[x] is not null but current request is of i915 self.
So instead we check ctx flag CONTEXT_FORCE_SINGLE_SUBMISSION. Only gvt
request set this flag and always set.

v2: Reverse the order of multi-condition 'if' statement.

Fixes: ab9da6279 ("drm/i915: make context status notifier head be per engine")
Signed-off-by: NChangbin Du <changbin.du@intel.com>
Reviewed-by: NYulei Zhang <yulei.zhang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

GVTg has introduced the context status notifier to schedule the GVTg
workload. At that time, the notifier is bound to GVTg context only,
so GVTg is not aware of host workloads.

Now we are going to improve GVTg's guest workload scheduler policy,
and add Guc emulation support for new Gen graphics. Both these two
features require acknowledgment for all contexts running on hardware.
(But will not alter host workload.) So here try to make some change.

The change is simple:
  1. Move the context status notifier head from i915_gem_context to
     intel_engine_cs. Which means there is a notifier head per engine
     instead of per context. Execlist driver still call notifier for
     each context sched-in/out events of current engine.
  2. At GVTg side, it binds a notifier_block for each physical engine
     at GVTg initialization period. Then GVTg can hear all context
     status events.

In this patch, GVTg do nothing for host context event, but later
will add a function there. But in any case, the notifier callback is
a noop if this is no active vGPU.

Since intel_gvt_init() is called at early initialization stage and
require the status notifier head has been initiated, I initiate it in
intel_engine_setup().

v2: remove a redundant newline. (chris)

Fixes: 3c7ba635 ("drm/i915: Introduce execlist context status change notification")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100232Signed-off-by: NChangbin Du <changbin.du@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170313024711.28591-1-changbin.du@intel.comAcked-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
(cherry picked from commit 3fc03069)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170321144720.17020-1-chris@chris-wilson.co.uk

The only time we need to emit a flush inside request emission is after
an execbuffer, for which we can use the full __i915_add_request(). All
other instances want the simpler i915_add_request() without flushing, so
remove the useless helper.
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/20170317114709.8388-1-chris@chris-wilson.co.uk

When handling guest request, GVT needs to populate/update shadow_ctx
with guest context. This behavior needs to make sure the shadow_ctx
is pinned. The current implementation is relying on i195 allocate request
to pin but this way cannot guarantee the i915 not to unpin the shadow_ctx
when GVT update the guest context from shadow_ctx. So GVT should pin/unpin
the shadow_ctx by itself.
Signed-off-by: NChuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

The shadow indirect context image should be only scanned when valid.
So far, Only RCS ring has the shadow indirect context image. This patch
limits the scan logic only for RCS ring.

v2. refine description of the subject
v3. fix alignment. (Zhenyu)
Signed-off-by: NTina Zhang <tina.zhang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

commit 8f1117ab ("drm/i915/gvt: handle workload lifecycle properly")
includes some nonsense to retry a indefinite wait - i915_wait_request()
does not return until the request is completed when used from an
uninterruptible context.

Fixes: 8f1117ab ("drm/i915/gvt: handle workload lifecycle properly"
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Chuanxiao Dong <chuanxiao.dong@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

gvt_err should be used only for the very few critical error message
during host i915 drvier initialization. This patch
1. removes the redundant gvt_err;
2. creates a new gvt_vgpu_err to show errors caused by vgpu;
3. replaces the most gvt_err with gvt_vgpu_err;
4. leaves very few gvt_err for dumping gvt error during host gvt
   initialization.

v2. change name to gvt_vgpu_err and add vgpu id to the message. (Kevin)
    add gpu id to gvt_vgpu_err. (Zhi)
v3. remove gpu id from gvt_vgpu_err caller. (Zhi)
v4. add vgpu check to the gvt_vgpu_err macro. (Zhiyuan)
v5. add comments for v3 and v4.
v6. split the big patch into two, with this patch only for checking
    gvt_vgpu_err. (Zhenyu)
v7. rebase to staging branch
v8. rebase to fix branch
Signed-off-by: NTina Zhang <tina.zhang@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

GVTg has introduced the context status notifier to schedule the GVTg
workload. At that time, the notifier is bound to GVTg context only,
so GVTg is not aware of host workloads.

Now we are going to improve GVTg's guest workload scheduler policy,
and add Guc emulation support for new Gen graphics. Both these two
features require acknowledgment for all contexts running on hardware.
(But will not alter host workload.) So here try to make some change.

The change is simple:
  1. Move the context status notifier head from i915_gem_context to
     intel_engine_cs. Which means there is a notifier head per engine
     instead of per context. Execlist driver still call notifier for
     each context sched-in/out events of current engine.
  2. At GVTg side, it binds a notifier_block for each physical engine
     at GVTg initialization period. Then GVTg can hear all context
     status events.

In this patch, GVTg do nothing for host context event, but later
will add a function there. But in any case, the notifier callback is
a noop if this is no active vGPU.

Since intel_gvt_init() is called at early initialization stage and
require the status notifier head has been initiated, I initiate it in
intel_engine_setup().

v2: remove a redundant newline. (chris)

Fixes: 3c7ba635 ("drm/i915: Introduce execlist context status change notification")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100232Signed-off-by: NChangbin Du <changbin.du@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170313024711.28591-1-changbin.du@intel.comAcked-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>