Since the introduction of 'soft-rc6', we aim to park the device quickly
and that results in frequent idling of the whole device. Currently upon
idling we free the batch buffer pool, and so this renders the cache
ineffective for many workloads. If we want to have an effective cache of
recently allocated buffers available for reuse, we need to decouple that
cache from the engine powermanagement and make it timer based. As there
is no reason then to keep it within the engine (where it once made
retirement order easier to track), we can move it up the hierarchy to the
owner of the memory allocations.

v2: Hook up to debugfs/drop_caches to clear the cache on demand.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@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/20200430111819.10262-2-chris@chris-wilson.co.uk

In the near future, we will utilize the busy-stats on each engine to
approximate the C0 cycles of each, and use that as an input to a manual
RPS mechanism. That entails having busy-stats always enabled and so we
can remove the enable/disable routines and simplify the pmu setup. As a
consequence of always having the stats enabled, we can also show the
current active time via sysfs/engine/xcs/active_time_ns.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429205446.3259-1-chris@chris-wilson.co.uk

We need to keep the default context state around to instantiate new
contexts (aka golden rendercontext), and we also keep it pinned while
the engine is active so that we can quickly reset a hanging context.
However, the default contexts are large enough to merit keeping in
swappable memory as opposed to kernel memory, so we store them inside
shmemfs. Currently, we use the normal GEM objects to create the default
context image, but we can throw away all but the shmemfs file.

This greatly simplifies the tricky power management code which wants to
run underneath the normal GT locking, and we definitely do not want to
use any high level objects that may appear to recurse back into the GT.
Though perhaps the primary advantage of the complex GEM object is that
we aggressively cache the mapping, but here we are recreating the
vm_area everytime time we unpark. At the worst, we add a lightweight
cache, but first find a microbenchmark that is impacted.

Having started to create some utility functions to make working with
shmemfs objects easier, we can start putting them to wider use, where
GEM objects are overkill, such as storing persistent error state.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Ramalingam C <ramalingam.c@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429172429.6054-1-chris@chris-wilson.co.uk

The bspec is confusing on the nature of the upper 32bits of the LRC
descriptor. Once upon a time, it said that it uses the upper 32b to
decide if it should perform a lite-restore, and so we must ensure that
each unique context submitted to HW is given a unique CCID [for the
duration of it being on the HW]. Currently, this is achieved by using
a small circular tag, and assigning every context submitted to HW a
new id. However, this tag is being cleared on repinning an inflight
context such that we end up re-using the 0 tag for multiple contexts.

To avoid accidentally clearing the CCID in the upper 32bits of the LRC
descriptor, split the descriptor into two dwords so we can update the
GGTT address separately from the CCID.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1796
Fixes: 2935ed53 ("drm/i915: Remove logical HW ID")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428184751.11257-1-chris@chris-wilson.co.uk

If we find ourselves waiting on a MI_SEMAPHORE_WAIT, either within the
user batch or in our own preamble, the engine raises a
GT_WAIT_ON_SEMAPHORE interrupt. We can unmask that interrupt and so
respond to a semaphore wait by yielding the timeslice, if we have
another context to yield to!

The only real complication is that the interrupt is only generated for
the start of the semaphore wait, and is asynchronous to our
process_csb() -- that is, we may not have registered the timeslice before
we see the interrupt. To ensure we don't miss a potential semaphore
blocking forward progress (e.g. selftests/live_timeslice_preempt) we mark
the interrupt and apply it to the next timeslice regardless of whether it
was active at the time.

v2: We use semaphores in preempt-to-busy, within the timeslicing
implementation itself! Ergo, when we do insert a preemption due to an
expired timeslice, the new context may start with the missed semaphore
flagged by the retired context and be yielded, ad infinitum. To avoid
this, read the context id at the time of the semaphore interrupt and
only yield if that context is still active.

Fixes: 8ee36e04 ("drm/i915/execlists: Minimalistic timeslicing")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200407130811.17321-1-chris@chris-wilson.co.uk

While extremely unlikely to be populated, we could capture a request on
the virtual engine which we should free along with the virtual engine.

Fixes: 43acd651 ("drm/i915: Keep a per-engine request pool")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJanusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200403203303.10903-1-chris@chris-wilson.co.uk

Add a tiny per-engine request mempool so that we should always have a
request available for powermanagement allocations from tricky
contexts. This reserve is expected to be only used for kernel
contexts when barriers must be emitted [almost] without fail.

The main consumer for this reserved request is expected to be engine-pm,
for which we know that there will always be at least the previous pm
request that we can reuse under mempressure (so there should always be
a spare request for engine_park()).

This is an alternative to using a comparatively bulky mempool, which
requires custom handling for both our reserved allocation requirement
and to protect our TYPESAFE_BY_RCU slab cache. The advantage of mempool
would be that it would allow us to keep a larger per-engine request
pool. However, converting over to mempool is straightforward should the
need arise.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-and-tested-by: NJanusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200402184037.21630-1-chris@chris-wilson.co.uk

Insert a space so that the same fields between active/pending execlists
state are aligned.
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/20200401111554.6279-1-chris@chris-wilson.co.uk

Since we print out EXECLISTS_STATUS in the dump, also print out the CCID
of each context so we can cross check between the two.
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/20200331094239.23145-1-chris@chris-wilson.co.uk

We've migrated all the heavy users over to the intel_gt, and can finally
drop the last few users and with that the mirror in dev_priv->engine[].
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200325234803.6175-1-chris@chris-wilson.co.uk

Allow super long OpenCL workloads which cannot be preempted within
the default timeout to run out of the box.

v2:
 * Make it stick out more and apply only to RCS. (Chris)

v3:
 * Mention platform override in kconfig. (Joonas)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michal Mrozek <michal.mrozek@intel.com>
Cc: <stable@vger.kernel.org> # v5.6+
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NMichal Mrozek <Michal.mrozek@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200312115748.29970-1-tvrtko.ursulin@linux.intel.com

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
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/20200311073256.6535-1-tiwai@suse.de

We busywait on an inflight request (one that is currently executing on
HW, and so might complete quickly) prior to setting up an interrupt and
sleeping. The trade off is that we keep an expensive CPU core busy in
order to avoid wake up latency: where that trade off should lie is best
left to the sysadmin.

The busywait mechanism can be compiled out with

	./scripts/config --set-val DRM_I915_SPIN_REQUEST 0

The maximum busywait duration can be adjusted per-engine using,

	/sys/class/drm/card?/engine/*/ms_busywait_duration_ns
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NSteve Carbonari <steven.carbonari@intel.com>
Tested-by: NSteve Carbonari <steven.carbonari@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-4-chris@chris-wilson.co.uk

Variable dw is being initialized with a value that is never read,
it is assigned a new value later on. The assignment is redundant
and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.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/20200222134755.134209-1-colin.king@canonical.com

As we have the total runtime known to us, show it when dumping the
engine state for debug.
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/20200218162150.1300405-2-chris@chris-wilson.co.uk

In order to support out-of-line error capture, we need to remove the
active request from HW and put it to one side while a worker compresses
and stores all the details associated with that request. (As that
compression may take an arbitrary user-controlled amount of time, we
want to let the engine continue running on other workloads while the
hanging request is dumped.) Not only do we need to remove the active
request, but we also have to remove its context and all requests that
were dependent on it (both in flight, queued and future submission).

Finally once the capture is complete, we need to be able to resubmit the
request and its dependents and allow them to execute.

v2: Replace stack recursion with a simple list.
v3: Check all the parents, not just the first, when searching for a
stuck ancestor!

References: https://gitlab.freedesktop.org/drm/intel/issues/738Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200116184754.2860848-2-chris@chris-wilson.co.uk
(cherry picked from commit 32ff621f)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

We set up a dummy ring in order to measure the size we require for our
breadcrumb emission, so that we don't have to manually count dwords! We
can pass in the kernel_context to use for this so that if required it is
known for the breadcrumb emitter, and we can reuse some details from the
kernel_context to reduce the number of temporaries we have to mock.
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/20200207125827.2787472-1-chris@chris-wilson.co.uk

The workarounds are a common "feature" across gens and submission
mechanisms and we already call the other WA related functions from
common engine ones (<setup/cleanup>_common), so it makes sense to
do the same with WA application. Medium-term, This will help us
reduce the duplication once the GuC resume function is added, but short
term it will also allow us to use the workaround lists for pre-gen8
engine workarounds.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Matthew Brost <matthew.brost@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/20200131075716.2212299-2-chris@chris-wilson.co.uk

On Braswell and Broxton (also known as Valleyview and Apollolake), we
need to serialise updates of the GGTT using the big stop_machine()
hammer. This has the side effect of appearing to lockdep as a possible
reclaim (since it uses the cpuhp mutex and that is tainted by per-cpu
allocations). However, we want to use vm->mutex (including ggtt->mutex)
from within the shrinker and so must avoid such possible taints. For this
purpose, we introduced the asynchronous vma binding and we can apply it
to the PIN_GLOBAL so long as take care to add the necessary waits for
the worker afterwards.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/211Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200130181710.2030251-3-chris@chris-wilson.co.uk

Conversion of the remaining printk based drm logging macros to the new
struct drm_device based logging macros in i915/gt/intel_engine_cs.c.
Signed-off-by: NWambui Karuga <wambui.karugax@gmail.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200128071437.9284-5-wambui.karugax@gmail.com

Could be helpful for debugging purposes.
Signed-off-by: NLionel Landwerlin <lionel.g.landwerlin@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/20200129181638.1528150-1-lionel.g.landwerlin@intel.com

Now that we have offline error capture and can reset an engine from
inside an atomic context while also preserving the GPU state for
post-mortem analysis, it is time to handle error interrupts thrown by
the command parser.

This provides a much, much faster mechanism for us to detect known
problems than using heartbeats/hangchecks, and also provides a mechanism
for when those are disabled. However, it is limited to problems the HW
can detect in the CS and so not a complete solution for detecting lockups.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200128204318.4182039-2-chris@chris-wilson.co.uk

Due to the asynchronous nature of releasing our wakerefs, we can signal
the main GT wakeref as complete before the individual engines have
cleared their own wakerefs. During shutdown we assert that the engines
are indeed parked before we release them, but for this to be always true
we need to flush their workers as well.
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/20200124143339.140988-1-chris@chris-wilson.co.uk

drm specific WARN* calls include device information in the
backtrace, so we know what device the warnings originate from.

Covert all the calls of WARN* with device specific drm_WARN*
variants in functions where drm_i915_private struct pointer is readily
available.

The conversion was done automatically with below coccinelle semantic
patch. checkpatch errors/warnings are fixed manually.

@rule1@
identifier func, T;
@@
func(...) {
...
struct drm_i915_private *T = ...;
<+...
(
-WARN(
+drm_WARN(&T->drm,
...)
|
-WARN_ON(
+drm_WARN_ON(&T->drm,
...)
|
-WARN_ONCE(
+drm_WARN_ONCE(&T->drm,
...)
|
-WARN_ON_ONCE(
+drm_WARN_ON_ONCE(&T->drm,
...)
)
...+>
}

@rule2@
identifier func, T;
@@
func(struct drm_i915_private *T,...) {
<+...
(
-WARN(
+drm_WARN(&T->drm,
...)
|
-WARN_ON(
+drm_WARN_ON(&T->drm,
...)
|
-WARN_ONCE(
+drm_WARN_ONCE(&T->drm,
...)
|
-WARN_ON_ONCE(
+drm_WARN_ON_ONCE(&T->drm,
...)
)
...+>
}

command: spatch --sp-file <script> --dir drivers/gpu/drm/i915/gt \
					--linux-spacing --in-place
Signed-off-by: NPankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200115034455.17658-7-pankaj.laxminarayan.bharadiya@intel.com

Just in the very unlikely case we have not stopped the GPU before we
return the pages being used by the GPU to the system, force a reset.
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/20200117180309.3249427-1-chris@chris-wilson.co.uk

Since commit 22b7a426 ("drm/i915/execlists: Preempt-to-busy"), we
prune the engine->active.requests list prior to preemption, thus
removing the trace of the currently executing request. If that request
hangs rather than be preempted, we conclude that no active request was
on the GPU. Fortunately, this only impacts our debugging, and not our
means of hang detection or recovery.

v2: Use from to check the current iterator before continuing, and report
active as NULL if the current request is already completed.

References: 22b7a426 ("drm/i915/execlists: Preempt-to-busy")
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/20200117113259.3023890-1-chris@chris-wilson.co.uk

In order to support out-of-line error capture, we need to remove the
active request from HW and put it to one side while a worker compresses
and stores all the details associated with that request. (As that
compression may take an arbitrary user-controlled amount of time, we
want to let the engine continue running on other workloads while the
hanging request is dumped.) Not only do we need to remove the active
request, but we also have to remove its context and all requests that
were dependent on it (both in flight, queued and future submission).

Finally once the capture is complete, we need to be able to resubmit the
request and its dependents and allow them to execute.

v2: Replace stack recursion with a simple list.
v3: Check all the parents, not just the first, when searching for a
stuck ancestor!

References: https://gitlab.freedesktop.org/drm/intel/issues/738Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200116184754.2860848-2-chris@chris-wilson.co.uk

In the near future, we will want to start a GPU error capture from a new
context, from inside the softirq region of a forced preemption. To do
so requires us to break up the monolithic error capture to provide new
entry points with finer control; in particular focusing on one
engine/gt, and being able to compose an error state from little pieces
of HW capture.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200110123059.1348712-1-chris@chris-wilson.co.uk

Our goal in wait_for_idle (intel_gt_retire_requests) is to the current
workload *and* their idle barriers. This requires us to notice the late
arrival of those, which is done by inspecting the list of active
timelines. However, if a concurrent retirer is running that new timeline
may not be added until after we drop the lock -- so flush concurrent
retirers before we take the lock and inspect the list.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/878Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191223211008.2371613-1-chris@chris-wilson.co.uk

Now that we don't need to create GEM contexts in the middle of engine
construction, we can pull the engine init/setup loops together.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191222144046.1674865-2-chris@chris-wilson.co.uk

Begin pulling the GT setup underneath a single GT umbrella; let intel_gt
take ownership of its engines! As hinted, the complication is the
lifetime of the probed engine versus the active lifetime of the GT
backends. We need to detect the engine layout early and keep it until
the end so that we can sanitize state on takeover and release.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191222120752.1368352-1-chris@chris-wilson.co.uk

Since we may retire timelines from secondary workers,
intel_gt_retire_requests() is not always a reliable indicator that all
pending retirements are complete. If we do detect secondary workers are
in progress, recommend intel_gt_wait_for_idle() to repeat the retirement
check.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191221180204.1201217-1-chris@chris-wilson.co.uk

Allocate only an internal intel_context for the kernel_context, forgoing
a global GEM context for internal use as we only require a separate
address space (for our own protection).

Now having weaned GT from requiring ce->gem_context, we can stop
referencing it entirely. This also means we no longer have to create random
and unnecessary GEM contexts for internal use.

GEM contexts are now entirely for tracking GEM clients, and intel_context
the execution environment on the GPU.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191221160324.1073045-1-chris@chris-wilson.co.uk

Keep the intel_context as being the primary state for i915_request, with
the GEM context a backpointer from the low level state for the rarer
cases we need client information. Our goal is to remove such references
to clients from the backend, and leave the HW submission agnostic to
client interfaces and self-contained.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191220101230.256839-1-chris@chris-wilson.co.uk

Knowing the round trip time of an engine is useful for tracking the
health of the system as well as providing a metric for the baseline
responsiveness of the engine. We can use the latter metric for
automatically tuning our waits in selftests and when idling so we don't
confuse a slower system with a dead one.

Upon idling the engine, we send one last pulse to switch the context
away from precious user state to the volatile kernel context. We know
the engine is idle at this point, and the pulse is non-preemptible, so
this provides us with a good measurement of the round trip time. It also
provides us with faster engine parking for ringbuffer submission, which
is a welcome bonus (e.g. softer-rc6).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191219105043.4169050-1-chris@chris-wilson.co.uk
Link: https://patchwork.freedesktop.org/patch/msgid/20191219124353.8607-2-chris@chris-wilson.co.uk

New macros ENGINE_TRACE(), CE_TRACE(), RQ_TRACE() and
GT_TRACE() are introduce to tag device name and engine
name with contexts and requests tracing in i915.

Cc: Sudeep Dutt <sudeep.dutt@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: NVenkata Sandeep Dhanalakota <venkata.s.dhanalakota@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/20191213155152.69182-2-venkata.s.dhanalakota@intel.com

Get rid of the last remaining I915_READ in gt/ and make gt-land
the first I915_READ-free happy island.
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NAndi Shyti <andi.shyti@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/20191205164422.727968-1-chris@chris-wilson.co.uk

We have a case of a mysteriously absent pulse, so dump the engine
details to see if we can find out what happened to it.

References: https://bugs.freedesktop.org/show_bug.cgi?id=112405Signed-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/20191128102546.3857140-1-chris@chris-wilson.co.uk

The major drawback of commit 7e34f4e4 ("drm/i915/gen8+: Add RC6 CTX
corruption WA") is that it disables RC6 while Skylake (and friends) is
active, and we do not consider the GPU idle until all outstanding
requests have been retired and the engine switched over to the kernel
context. If userspace is idle, this task falls onto our background idle
worker, which only runs roughly once a second, meaning that userspace has
to have been idle for a couple of seconds before we enable RC6 again.
Naturally, this causes us to consume considerably more energy than
before as powersaving is effectively disabled while a display server
(here's looking at you Xorg) is running.

As execlists will get a completion event as each context is completed,
we can use this interrupt to queue a retire worker bound to this engine
to cleanup idle timelines. We will then immediately notice the idle
engine (without userspace intervention or the aid of the background
retire worker) and start parking the GPU. Thus during light workloads,
we will do much more work to idle the GPU faster...  Hopefully with
commensurate power saving!

v2: Watch context completions and only look at those local to the engine
when retiring to reduce the amount of excess work we perform.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112315
References: 7e34f4e4 ("drm/i915/gen8+: Add RC6 CTX corruption WA")
References: 2248a283 ("drm/i915/gen8+: Add RC6 CTX corruption WA")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191125105858.1718307-3-chris@chris-wilson.co.uk
(cherry picked from commit 4f88f874)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

The major drawback of commit 7e34f4e4 ("drm/i915/gen8+: Add RC6 CTX
corruption WA") is that it disables RC6 while Skylake (and friends) is
active, and we do not consider the GPU idle until all outstanding
requests have been retired and the engine switched over to the kernel
context. If userspace is idle, this task falls onto our background idle
worker, which only runs roughly once a second, meaning that userspace has
to have been idle for a couple of seconds before we enable RC6 again.
Naturally, this causes us to consume considerably more energy than
before as powersaving is effectively disabled while a display server
(here's looking at you Xorg) is running.

As execlists will get a completion event as each context is completed,
we can use this interrupt to queue a retire worker bound to this engine
to cleanup idle timelines. We will then immediately notice the idle
engine (without userspace intervention or the aid of the background
retire worker) and start parking the GPU. Thus during light workloads,
we will do much more work to idle the GPU faster...  Hopefully with
commensurate power saving!

v2: Watch context completions and only look at those local to the engine
when retiring to reduce the amount of excess work we perform.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112315
References: 7e34f4e4 ("drm/i915/gen8+: Add RC6 CTX corruption WA")
References: 2248a283 ("drm/i915/gen8+: Add RC6 CTX corruption WA")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191125105858.1718307-3-chris@chris-wilson.co.uk