If we have multiple contexts of equal priority pending execution,
activate a timer to demote the currently executing context in favour of
the next in the queue when that timeslice expires. This enforces
fairness between contexts (so long as they allow preemption -- forced
preemption, in the future, will kick those who do not obey) and allows
us to avoid userspace blocking forward progress with e.g. unbounded
MI_SEMAPHORE_WAIT.

For the starting point here, we use the jiffie as our timeslice so that
we should be reasonably efficient wrt frequent CPU wakeups.

Testcase: igt/gem_exec_scheduler/semaphore-resolve
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190620142052.19311-2-chris@chris-wilson.co.uk

When using a global seqno, we required a precise stop-the-workd event to
handle preemption and unwind the global seqno counter. To accomplish
this, we would preempt to a special out-of-band context and wait for the
machine to report that it was idle. Given an idle machine, we could very
precisely see which requests had completed and which we needed to feed
back into the run queue.

However, now that we have scrapped the global seqno, we no longer need
to precisely unwind the global counter and only track requests by their
per-context seqno. This allows us to loosely unwind inflight requests
while scheduling a preemption, with the enormous caveat that the
requests we put back on the run queue are still _inflight_ (until the
preemption request is complete). This makes request tracking much more
messy, as at any point then we can see a completed request that we
believe is not currently scheduled for execution. We also have to be
careful not to rewind RING_TAIL past RING_HEAD on preempting to the
running context, and for this we use a semaphore to prevent completion
of the request before continuing.

To accomplish this feat, we change how we track requests scheduled to
the HW. Instead of appending our requests onto a single list as we
submit, we track each submission to ELSP as its own block. Then upon
receiving the CS preemption event, we promote the pending block to the
inflight block (discarding what was previously being tracked). As normal
CS completion events arrive, we then remove stale entries from the
inflight tracker.

v2: Be a tinge paranoid and ensure we flush the write into the HWS page
for the GPU semaphore to pick in a timely fashion.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190620142052.19311-1-chris@chris-wilson.co.uk

Remember to keep the rings pinned as well as the context image until the
GPU is no longer active.

v2: Introduce a ring->pin_count primarily to hide the
mock_ring that doesn't fit into the normal GGTT vma picture.

v3: Order is important in teardown, ringbuffer submission needs to drop
the pin count on the engine->kernel_context before it can gleefully free
its ring.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110946
Fixes: ce476c80 ("drm/i915: Keep contexts pinned until after the next kernel context switch")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190619170135.15281-1-chris@chris-wilson.co.uk

Since commit eb8d0f5a ("drm/i915: Remove GPU reset dependence on
struct_mutex"), the I915_WAIT_LOCKED flags passed to i915_request_wait()
has been defunct. Now go ahead and remove it from all callers.

References: eb8d0f5a ("drm/i915: Remove GPU reset dependence on struct_mutex")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618074153.16055-3-chris@chris-wilson.co.uk

The process_csb routine from execlists_submission is incompatible with
the GuC backend. Add a warning to detect if we accidentally end up in
the wrong spot.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618110736.31155-1-chris@chris-wilson.co.uk

The idea behind keeping the saturation mask local to a context backfired
spectacularly. The premise with the local mask was that we would be more
proactive in attempting to use semaphores after each time the context
idled, and that all new contexts would attempt to use semaphores
ignoring the current state of the system. This turns out to be horribly
optimistic. If the system state is still oversaturated and the existing
workloads have all stopped using semaphores, the new workloads would
attempt to use semaphores and be deprioritised behind real work. The
new contexts would not switch off using semaphores until their initial
batch of low priority work had completed. Given sufficient backload load
of equal user priority, this would completely starve the new work of any
GPU time.

To compensate, remove the local tracking in favour of keeping it as
global state on the engine -- once the system is saturated and
semaphores are disabled, everyone stops attempting to use semaphores
until the system is idle again. One of the reason for preferring local
context tracking was that it worked with virtual engines, so for
switching to global state we could either do a complete check of all the
virtual siblings or simply disable semaphores for those requests. This
takes the simpler approach of disabling semaphores on virtual engines.

The downside is that the decision that the engine is saturated is a
local measure -- we are only checking whether or not this context was
scheduled in a timely fashion, it may be legitimately delayed due to user
priorities. We still have the same dilemma though, that we do not want
to employ the semaphore poll unless it will be used.

v2: Explain why we need to assume the worst wrt virtual engines.

Fixes: ca6e56f6 ("drm/i915: Disable semaphore busywaits on saturated systems")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Cc: Dmitry Ermilov <dmitry.ermilov@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618074153.16055-8-chris@chris-wilson.co.uk

This has caught me out on countless occasions, when we retrieve a pointer
from the submission/execlists backend, it does not carry a reference to
the context or ring. Those are only pinned while the request is active,
so if we see the request is already completed, it may be in the process
of being retired and those pointers defunct.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110938
Fixes: 3a068721 ("drm/i915: Show ring->start for the ELSP context/request queue")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618161951.28820-2-chris@chris-wilson.co.uk

Updates the live_workarounds selftest to handle whitelisted
registers that are flagged as read only.
Signed-off-by: NRobert M. Fosha <robert.m.fosha@intel.com>
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618010108.27499-5-John.C.Harrison@Intel.com

Updated whitelist table for ICL.

v2: Reduce changes to just those required for media driver until
the selftest can be updated to support the new features of the
other entries.
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NRobert M. Fosha <robert.m.fosha@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618010108.27499-4-John.C.Harrison@Intel.com

Newer hardware requires setting up whitelists on engines other than
render. So, extend the whitelist code to support all engines.
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NRobert M. Fosha <robert.m.fosha@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618010108.27499-3-John.C.Harrison@Intel.com

Newer hardware adds flags to the whitelist work-around register. These
allow per access direction privileges and ranges.
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NRobert M. Fosha <robert.m.fosha@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618010108.27499-2-John.C.Harrison@Intel.com

All page directories are identical in function, only the position in the
hierarchy differ. Use same base type for directory functionality.

v2: cleanup, size always 512, init to null

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164350.30415-2-mika.kuoppala@linux.intel.com

Now that we have a new subdirectory for display code, continue by moving
modesetting core code.

display/intel_frontbuffer.h sticks out like a sore thumb, otherwise this
is, again, a surprisingly clean operation.

v2:
- don't move intel_sideband.[ch] (Ville)
- use tabs for Makefile file lists and sort them

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613084416.6794-3-jani.nikula@intel.com

EHL defines two new MOCS table entries but is otherwise compatible with
the ICL MOCS table.

These table entries (16 and 17) should still be considered unused for
ICL and as such their behavior remains undefined for that platform.
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190530234014.22340-1-matthew.d.roper@intel.comReviewed-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>

To continue the onslaught of removing the assumption of a global
execution ordering, another casualty is the engine->timeline. Without an
actual timeline to track, it is overkill and we can replace it with a
much less grand plain list. We still need a list of requests inflight,
for the simple purpose of finding inflight requests (for retiring,
resetting, preemption etc).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164606.15633-3-chris@chris-wilson.co.uk

We need to keep the context image pinned in memory until after the GPU
has finished writing into it. Since it continues to write as we signal
the final breadcrumb, we need to keep it pinned until the request after
it is complete. Currently we know the order in which requests execute on
each engine, and so to remove that presumption we need to identify a
request/context-switch we know must occur after our completion. Any
request queued after the signal must imply a context switch, for
simplicity we use a fresh request from the kernel context.

The sequence of operations for keeping the context pinned until saved is:

 - On context activation, we preallocate a node for each physical engine
   the context may operate on. This is to avoid allocations during
   unpinning, which may be from inside FS_RECLAIM context (aka the
   shrinker)

 - On context deactivation on retirement of the last active request (which
   is before we know the context has been saved), we add the
   preallocated node onto a barrier list on each engine

 - On engine idling, we emit a switch to kernel context. When this
   switch completes, we know that all previous contexts must have been
   saved, and so on retiring this request we can finally unpin all the
   contexts that were marked as deactivated prior to the switch.

We can enhance this in future by flushing all the idle contexts on a
regular heartbeat pulse of a switch to kernel context, which will also
be used to check for hung engines.

v2: intel_context_active_acquire/_release
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164606.15633-1-chris@chris-wilson.co.uk

intel_runtime_pm is the only thing they use from the i915 structure,
so use that directly.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-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/20190613232156.34940-9-daniele.ceraolospurio@intel.com

Matching the underlying get/put functions.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613232156.34940-8-daniele.ceraolospurio@intel.com

The functions where internally already only using the structure, so we
need to just flip the interface.

v2: rebase
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613232156.34940-7-daniele.ceraolospurio@intel.com

We already use a mutex to serialise i915_reset() and wedging, so all we
need it to link that into i915_request_wait() and we have our lock cycle
detection.

v2.5: Take error mutex for selftests
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614071023.17929-3-chris@chris-wilson.co.uk

Since commit a679f58d ("drm/i915: Flush pages on acquisition"), we
flush objects on acquire their pages and as such when we create an
object for the purpose of writing into it, we do not need to manually
flush.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614111053.25615-1-chris@chris-wilson.co.uk

As the fence registers only apply to regions inside the GGTT is makes
more sense that we track these as part of the i915_ggtt and not the
general mm. In the next patch, we will then pull the register locking
underneath the i915_ggtt.mutex.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613073254.24048-1-chris@chris-wilson.co.uk

Remove call sites in favour of uncore mmio accessors and remove the old
macros.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190611104548.30545-6-tvrtko.ursulin@linux.intel.com

Only a few call sites remain which have been converted to uncore mmio
accessors and so the macro can be removed.

ENGINE_POSTING_READ16 is added to replace one engine->mmio_base relative
call site.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190611104548.30545-3-tvrtko.ursulin@linux.intel.com

We cannot allow ourselves to wait on the GPU while holding any lock as we
may need to reset the GPU. While there is not an explicit lock between
the two operations, lockdep cannot detect the dependency. So let's tell
lockdep about the wait/reset dependency with an explicit lockmap.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190612085246.16374-1-chris@chris-wilson.co.uk

Keeping the _hw_ in there does not help to distinguish it from its
only brethren i915_ggtt, so drop it.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190611091238.15808-2-chris@chris-wilson.co.uk

Make the kref common to both derived structs (i915_ggtt and i915_ppgtt)
so that we can safely reference count an abstract ctx->vm address space.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190611091238.15808-1-chris@chris-wilson.co.uk

Before we commit ourselves to writing commands into the
ringbuffer and submitting the request, allow signals to interrupt
acquisition of the timeline mutex. We allow ourselves to be interrupted
at any time later if we need to block for space in the ring, anyway.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190610103610.19883-1-chris@chris-wilson.co.uk

The function operates on the render engine so make the input reflect it.

v2:
 * Pass engine to read_subslice_reg. (Chris)
 * Drop inline from read_subslice_reg.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Suggested-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190610125706.26110-1-tvrtko.ursulin@linux.intel.com

The code is logically about reset so it makes sense.

It also enables making i915_clear_error_registers static.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607115932.20271-1-tvrtko.ursulin@linux.intel.com

Get to uncore from the engine for better logic organization and use
already available i915 everywhere.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Suggested-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607084521.16845-2-tvrtko.ursulin@linux.intel.com

Remove a couple dev_priv locals as a consequence.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607084521.16845-1-tvrtko.ursulin@linux.intel.com

Just tidying the flow a bit.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607082557.31670-4-tvrtko.ursulin@linux.intel.com

Similar to earlier conversions, eliminate the implicit dev_priv by
introducing some helpers which take the engine parameter (since the
register itself is per engine).

v2:
 * Always use parentheses in macro arguments.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607101535.767-1-tvrtko.ursulin@linux.intel.com

We can use intel_engine_mask_t to align with the rest of the codebase.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607082557.31670-2-tvrtko.ursulin@linux.intel.com

Pass down the engine mask to i915_clear_error_registers so only affected
engines can be reset on the Gen6/7 path.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607082557.31670-1-tvrtko.ursulin@linux.intel.com

The plan is to use the blitter engine for async object clearing when
using local memory, but before we can move the worker to get_pages() we
have to first tame some more of our struct_mutex usage. With this in
mind we should be able to upstream the object clearing as some
selftests, which should serve as a guinea pig for the ongoing locking
rework and upcoming async get_pages() framework.
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: CQ Tang <cq.tang@intel.com>
Reviewed-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/20190529123108.24422-2-matthew.auld@intel.com

This reverts commit 1ac159e2 ("drm/i915: Expand subslice mask"),
which kills ICL due to GEM_BUG_ON() sanity checks before CI even gets a
chance to do anything.

The commit exposes an issue in commit 1e40d4ae ("drm/i915/cnl:
Implement WaProgramMgsrForCorrectSliceSpecificMmioReads"), which will
also need to be addressed.

There's a proposed fix [1], but considering the seeming uncertainty with
the fix as well as the size of the regressing commit (in this context,
the one that actually brings down ICL), this warrants a revert to get
ICL working, and gives us time to get all of this right without
rushing. Even if this means shooting the messenger.

<3>[    9.426327] intel_sseu_get_subslices:46 GEM_BUG_ON(slice >= sseu->max_slices)
<4>[    9.426355] ------------[ cut here ]------------
<2>[    9.426357] kernel BUG at drivers/gpu/drm/i915/gt/intel_sseu.c:46!
<4>[    9.426371] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
<4>[    9.426377] CPU: 1 PID: 364 Comm: systemd-udevd Not tainted 5.2.0-rc2-CI-CI_DRM_6159+ #1
<4>[    9.426385] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3183.A00.1905020411 05/02/2019
<4>[    9.426444] RIP: 0010:intel_sseu_get_subslices+0x8a/0xe0 [i915]
<4>[    9.426452] Code: d5 76 b7 e0 48 8b 35 9d 24 21 00 49 c7 c0 07 f0 72 a0 b9 2e 00 00 00 48 c7 c2 00 8e 6d a0 48 c7 c7 a5 14 5b a0 e8 36 3c be e0 <0f> 0b 48 c7 c1 80 d5 6f a0 ba 30 00 00 00 48 c7 c6 00 8e 6d a0 48
<4>[    9.426468] RSP: 0018:ffffc9000037b9c8 EFLAGS: 00010282
<4>[    9.426475] RAX: 000000000000000f RBX: 0000000000000000 RCX: 0000000000000000
<4>[    9.426482] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88849e346f98
<4>[    9.426490] RBP: ffff88848a200000 R08: 0000000000000004 R09: ffff88849d50b000
<4>[    9.426497] R10: 0000000000000000 R11: ffff88849e346f98 R12: ffff88848a209e78
<4>[    9.426505] R13: 0000000003000000 R14: ffff88848a20b1a8 R15: 0000000000000000
<4>[    9.426513] FS:  00007f73d5ae8680(0000) GS:ffff88849fc80000(0000) knlGS:0000000000000000
<4>[    9.426521] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[    9.426527] CR2: 0000561417b01260 CR3: 0000000494764003 CR4: 0000000000760ee0
<4>[    9.426535] PKRU: 55555554
<4>[    9.426538] Call Trace:
<4>[    9.426585]  wa_init_mcr+0xd5/0x110 [i915]
<4>[    9.426597]  ? lock_acquire+0xa6/0x1c0
<4>[    9.426645]  icl_gt_workarounds_init+0x21/0x1a0 [i915]
<4>[    9.426694]  ? i915_driver_load+0xfcf/0x18a0 [i915]
<4>[    9.426739]  gt_init_workarounds+0x14c/0x230 [i915]
<4>[    9.426748]  ? _raw_spin_unlock_irq+0x24/0x50
<4>[    9.426789]  intel_gt_init_workarounds+0x1b/0x30 [i915]
<4>[    9.426835]  i915_driver_load+0xfd7/0x18a0 [i915]
<4>[    9.426843]  ? lock_acquire+0xa6/0x1c0
<4>[    9.426850]  ? __pm_runtime_resume+0x4f/0x80
<4>[    9.426857]  ? _raw_spin_unlock_irqrestore+0x4c/0x60
<4>[    9.426863]  ? _raw_spin_unlock_irqrestore+0x4c/0x60
<4>[    9.426870]  ? lockdep_hardirqs_on+0xe3/0x1b0
<4>[    9.426915]  i915_pci_probe+0x29/0xa0 [i915]
<4>[    9.426923]  pci_device_probe+0x9e/0x120
<4>[    9.426930]  really_probe+0xea/0x3c0
<4>[    9.426936]  driver_probe_device+0x10b/0x120
<4>[    9.426942]  device_driver_attach+0x4a/0x50
<4>[    9.426948]  __driver_attach+0x97/0x130
<4>[    9.426954]  ? device_driver_attach+0x50/0x50
<4>[    9.426960]  bus_for_each_dev+0x74/0xc0
<4>[    9.426966]  bus_add_driver+0x13f/0x210
<4>[    9.426971]  ? 0xffffffffa083b000
<4>[    9.426976]  driver_register+0x56/0xe0
<4>[    9.426982]  ? 0xffffffffa083b000
<4>[    9.426987]  do_one_initcall+0x58/0x300
<4>[    9.426994]  ? do_init_module+0x1d/0x1f6
<4>[    9.427001]  ? rcu_read_lock_sched_held+0x6f/0x80
<4>[    9.427007]  ? kmem_cache_alloc_trace+0x261/0x290
<4>[    9.427014]  do_init_module+0x56/0x1f6
<4>[    9.427020]  load_module+0x24d1/0x2990
<4>[    9.427032]  ? __se_sys_finit_module+0xd3/0xf0
<4>[    9.427037]  __se_sys_finit_module+0xd3/0xf0
<4>[    9.427047]  do_syscall_64+0x55/0x1c0
<4>[    9.427053]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[    9.427059] RIP: 0033:0x7f73d5609839
<4>[    9.427064] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48
<4>[    9.427082] RSP: 002b:00007ffdf34477b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
<4>[    9.427091] RAX: ffffffffffffffda RBX: 00005559fd5d7b40 RCX: 00007f73d5609839
<4>[    9.427099] RDX: 0000000000000000 RSI: 00007f73d52e8145 RDI: 000000000000000f
<4>[    9.427106] RBP: 00007f73d52e8145 R08: 0000000000000000 R09: 00007ffdf34478d0
<4>[    9.427114] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000000
<4>[    9.427121] R13: 00005559fd5c90f0 R14: 0000000000020000 R15: 00005559fd5d7b40
<4>[    9.427131] Modules linked in: i915(+) mei_hdcp x86_pkg_temp_thermal coretemp snd_hda_intel crct10dif_pclmul crc32_pclmul snd_hda_codec snd_hwdep e1000e snd_hda_core ghash_clmulni_intel ptp snd_pcm cdc_ether usbnet mii pps_core mei_me mei prime_numbers btusb btrtl btbcm btintel bluetooth ecdh_generic ecc
<4>[    9.427254] ---[ end trace af3eeb543bd66e66 ]---

[1] http://patchwork.freedesktop.org/patch/msgid/20190528200655.11605-1-chris@chris-wilson.co.uk

References: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_6159/fi-icl-u2/pstore0-1517155098_Oops_1.log
References: 1e40d4ae ("drm/i915/cnl: Implement WaProgramMgsrForCorrectSliceSpecificMmioReads")
Fixes: 1ac159e2 ("drm/i915: Expand subslice mask")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Yunwei Zhang <yunwei.zhang@intel.com>
Acked-by: NDaniel Vetter <daniel@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190529082150.31526-1-jani.nikula@intel.com

We should check "request[n]" instead of just "request".

Fixes: 78e41ddd ("drm/i915: Apply an execution_mask to the virtual_engine")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-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/20190529110355.GA19119@mwanda

Currently, the subslice_mask runtime parameter is stored as an
array of subslices per slice. Expand the subslice mask array to
better match what is presented to userspace through the
I915_QUERY_TOPOLOGY_INFO ioctl. The index into this array is
then calculated:
  slice * subslice stride + subslice index / 8

v2: fix spacing in set_sseu_info args
    use set_sseu_info to initialize sseu data when building
    device status in debugfs
    rename variables in intel_engine_types.h to avoid checkpatch
    warnings
v3: update headers in intel_sseu.h
v4: add const to some sseu_dev_info variables
    use sseu->eu_stride for EU stride calculations
v5: address review comments from Tvrtko and Daniele
v6: remove extra space in intel_sseu_get_subslices
    return the correct subslice enable in for_each_instdone
    add GEM_BUG_ON to ensure user doesn't pass invalid ss_mask size
    use printk formatted string for subslice mask
v7: remove string.h header and rebase

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: NLionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: NStuart Summers <stuart.summers@intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190524154022.13575-6-stuart.summers@intel.com