Instead of sleeping for a fixed 1ms (roughly, depending on timer slack),
start with a small sleep and exponentially increase the sleep on each
cycle.

A good example of a beneficiary is the guc mmio communication channel.
Typically we expect (and so spin) for 10us for a quick response, but this
doesn't cover everything and so sometimes we fallback to the millisecond+
sleep. This incurs a significant delay in time-critical operations like
preemption (igt/gem_exec_latency), which can be improved significantly by
using a small sleep after the spin fails.

We've made this suggestion many times, but had little experimental data
to support adding the complexity.

v2: Bump the minimum usleep to 10us on advice of
Documentation/timers/timers-howto.txt (Tvrko)
v3: Specify min, max range for usleep intervals -- some code may
crucially depend upon and so want to specify the sleep pattern.

References: 1758b90e ("drm/i915: Use a hybrid scheme for fast register waits")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: John Harrison <John.C.Harrison@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Reviewed-by: NMichał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171124130031.20761-2-chris@chris-wilson.co.uk

Since we know that the port is empty, we do not need to extract the
count from the old request it and copy it over to the new request, or
attempt to unref the NULL old request pointer.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: NMichał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171124130031.20761-1-chris@chris-wilson.co.uk

Our execlist emulation is intended to only use a maximum of 2 ports per
engine, so as to not overflow the wq. (By knowing the limits, we can
avoid having to handle the wq exhaustion.) However, upon adding
preemption, we lost the skip over the first port if set for the
non-preemption path. Restore it.
Reported-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Fixes: c41937fd ("drm/i915/guc: Preemption! With GuC")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171124133745.5173-1-chris@chris-wilson.co.ukReviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMichał Winiarski <michal.winiarski@intel.com>

The hardware always writes one or two bytes in the index portion of
an indexed transfer. Make sure the message we send as the index
doesn't have a zero length.

Cc: stable@vger.kernel.org
Cc: Daniel Kurtz <djkurtz@chromium.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <seanpaul@chromium.org>
Fixes: 56f9eac0 ("drm/i915/intel_i2c: use INDEX cycles for i2c read transactions")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123194157.25367-3-ville.syrjala@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

We can only specify the one slave address to indexed reads/writes.
Make sure the messages we check are destined to the same slave
address before deciding to do an indexed transfer.

Cc: stable@vger.kernel.org
Cc: Daniel Kurtz <djkurtz@chromium.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <seanpaul@chromium.org>
Fixes: 56f9eac0 ("drm/i915/intel_i2c: use INDEX cycles for i2c read transactions")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123194157.25367-2-ville.syrjala@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Averaging with the previous sample brings a small statistical improvement
to sampling counters, but can leek a little bit of state from a current
client to the next which mulls the border between past and present for
observing clients.

This is because on event enable clients record the current counter value
and use it as reference, but with rapid off-on event cycles, and due the
delayed nature of sampling timer self-disarm, previous sample value does
not get cleared under these circumstances.

Solution is to stop averaging with the previous sample. This has a small
downside of losing some precision with short and spiky signals, but the
alternatives look too complicated for the benefit.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171124094959.10725-1-tvrtko.ursulin@linux.intel.com

Ensure that we build our test kernels with DEBUG_FS enabled as many of
our igt tests require poking around debugfs/dri.

This should also fixup the kbuild complaint that we tried to select
SW_SYNC without meeting its dependencies.

Reported-by: kbuild-all@01.org
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171012092147.28986-1-chris@chris-wilson.co.uk

We are using intel_ prefix for all file names with hardware
related definitions. GuC registers also fall into this category.
Signed-off-by: NMichal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Reviewed-by: NSagar Arun Kamble <sagar.a.kamble@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171124095340.1500-1-michal.wajdeczko@intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

While renaming i915_guc_submission.h to intel_guc_submission.h, update of
header guard name to _INTEL_GUC_SUBMISSION_H_ was missed.

References: a2695744 (drm/i915/guc: Rename i915_guc_submission.c|h to intel_guc_submission.c|h)
Signed-off-by: NSagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NMichal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1511511650-13756-1-git-send-email-sagar.a.kamble@intel.comSigned-off-by: NChris Wilson <chris@chris-wilson.co.uk>

We do two things, both of which are purely to simplify and clarify the
implementation:

1.

Simplify the CPU online callback so it is more obvious that the purpose
there is to set a single CPU mask bit for the first CPU which comes
online. Using cpumask_weight for this reads more obvious than the trick
with cpumask_and_any.

2.

Modify the event init so that events can be created only on a single CPU.

This removes looking at the requested CPU thread siblings, and only allows
creating on the current active CPU.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Tested-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123123432.25035-2-tvrtko.ursulin@linux.intel.com

Even for static CPU configurations, the hotplug CPU framework is still
used to determine the CPU topology, and is still being used by the perf
event register to check for valid CPUs.

Fixes: b46a33e2 ("drm/i915/pmu: Expose a PMU interface for perf queries")
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>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123123432.25035-1-tvrtko.ursulin@linux.intel.com

Since the removal of the delayed rc6 enabling, we now setup and drop the
early rpm wakeref during modules initialisation before we start the live
selftests. As such, we are now detecting errors in the tests where we
were not holding the required wakeref for various actions. As rpm is not
the primary goal of the tests involved, take a coarse and convenient rpm
wakeref around the tests.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123233712.21836-1-chris@chris-wilson.co.ukReviewed-by: NMatthew Auld <matthew.william.auld@gmail.com>

We pretend the PMU config id is a pointer value when encoding it into
the device parameters for presentation via sysfs. This requires casting
of an unsigned long into and out of the pointer member, which annoys
smatch:

drivers/gpu/drm/i915/i915_pmu.c:684 i915_pmu_event_show() warn: argument 3 to %lx specifier is cast from pointer

Instead of abusing a generic dev_ext_attribute, define our own typesafe
attributes.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123211751.2885-1-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

The legacy i915_switch_context() is only applicable to the legacy
ringbuffer submission method, so move it from the general
i915_gem_context.c to intel_ringbuffer.c (rename pending!).
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/20171123152631.31385-2-chris@chris-wilson.co.uk

The legacy context switch for ringbuffer submission is multistaged,
where each of those stages may fail. However, we were updating global
state after some stages, and so we had to force the incomplete request
to be submitted because we could not unwind. Save the global state
before performing the switches, and so enable us to unwind back to the
previous global state should any phase fail. We then must cancel the
request instead of submitting it should the construction fail.

v2: s/saved_ctx/from_ctx/; s/ctx/to_ctx/ etc.
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/20171123152631.31385-1-chris@chris-wilson.co.uk

For igt_write_huge make sure the higher gtt offsets don't feel left out,
which is especially true when dealing with the 48b PPGTT, where we
timeout long before we are able exhaust the address space.

v2: just use IGT_TIMEOUT
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
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/20171123135421.17967-2-matthew.auld@intel.com

Rather than repeat the test for each engine, which takes a long time,
let's try alternating between the engines in some randomized
order.

v2: fix gen2 blunder
    fix !order blunder
    more cunning permutation construction!
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
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/20171123135421.17967-1-matthew.auld@intel.com

This goes back to pre-atomic, where due to intermediate dpms states
connectors and encoder states might indeed not have matched.

With atomic that's all smashed together (and hopefully no bios ever
enables a vga output in dpms standby/suspedn state or we're toast).
In

commit 873ffe69
Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date:   Wed Aug 5 12:37:07 2015 +0200

    drm/i915: Remove connectors_active from sanitization, v2.

sanitize_encoders was changed to disable the encoder in all cases,
which made the comment obsolete.

Remove the misleading comment.
Reported-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171121094241.9129-1-daniel.vetter@ffwll.ch

Two bits:
- check actual atomic state, the legacy stuff can only be looked at
  from within the atomic_commit_tail function, since it's only
  protected by ordering and not by any locks.

- Make sure we don't wreak the work an ongoing nonblocking commit is
  doing.

v2: We need the crtc lock too, because a plane update might change it
without having to acquire the connection_mutex (Maarten). Use
Maarten's changes for this locking, while keeping the logic that uses
the connection->commit->hw_done signal for syncing with nonblocking
commits.

v3: The initial state objects from the hw state readout do not have a
commit object. Check for that (spotted by CI).

v4: Fix deadlock from jumping to put_power with locks still held.
    (mlankhorst)

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
References: https://bugs.freedesktop.org/show_bug.cgi?id=103336
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99272Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171113160140.22679-1-maarten.lankhorst@linux.intel.com

When turning off the engines, and the pmu sampling, clear the previous
value as the current measurement should be 0.

v2: Use a for-loop
v3:
 * Move clearing to timer self-dis-arm to avoid race with parking.
 * Clear frequency samples as well.
v4:
 * Init frequency to idle_freq. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v3)
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123102654.29296-1-tvrtko.ursulin@linux.intel.com

We have agreed during the engine classes discussion that fields marked as
non-ABI are better left out altogether from uapi headers.

v2: Use a local define for maintanability. (Chris Wilson)
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/20171123100701.18430-1-tvrtko.ursulin@linux.intel.com

There is a new version of DMC available for KBL.

The release notes mentions:
1. Fix for the issue where DC_STATE was getting enabled even
when disabled by driver causing data corruption.

v2: Remove pull request from commit message (Rodrigo).

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NAnusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1510253503-12634-1-git-send-email-anusha.srivatsa@intel.com

Since commit 6060b6ae ("drm/i915/pmu: Add RC6 residency metrics"),
vlv_residency_raw() may be called from an irq-disabled context (via perf
event sampling on remote cpu). As such, we can no longer assume that we
are called from process context and must save/restore the irq state for
the spinlock.

Fixes: 6060b6ae ("drm/i915/pmu: Add RC6 residency metrics")
Testcase: igt/perf_pmu/other-init-3
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171122222510.22627-1-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

We don't need struct_mutex to initialise userptr (it just allocates a
workqueue for itself etc), but we do need struct_mutex later on in
i915_gem_init() in order to feed requests onto the HW.

This should break the chain

[  385.697902] ======================================================
[  385.697907] WARNING: possible circular locking dependency detected
[  385.697913] 4.14.0-CI-Patchwork_7234+ #1 Tainted: G     U
[  385.697917] ------------------------------------------------------
[  385.697922] perf_pmu/2631 is trying to acquire lock:
[  385.697927]  (&mm->mmap_sem){++++}, at: [<ffffffff811bfe1e>] __might_fault+0x3e/0x90
[  385.697941]
               but task is already holding lock:
[  385.697946]  (&cpuctx_mutex){+.+.}, at: [<ffffffff8116fe8c>] perf_event_ctx_lock_nested+0xbc/0x1d0
[  385.697957]
               which lock already depends on the new lock.

[  385.697963]
               the existing dependency chain (in reverse order) is:
[  385.697970]
               -> #4 (&cpuctx_mutex){+.+.}:
[  385.697980]        __mutex_lock+0x86/0x9b0
[  385.697985]        perf_event_init_cpu+0x5a/0x90
[  385.697991]        perf_event_init+0x178/0x1a4
[  385.697997]        start_kernel+0x27f/0x3f1
[  385.698003]        verify_cpu+0x0/0xfb
[  385.698006]
               -> #3 (pmus_lock){+.+.}:
[  385.698015]        __mutex_lock+0x86/0x9b0
[  385.698020]        perf_event_init_cpu+0x21/0x90
[  385.698025]        cpuhp_invoke_callback+0xca/0xc00
[  385.698030]        _cpu_up+0xa7/0x170
[  385.698035]        do_cpu_up+0x57/0x70
[  385.698039]        smp_init+0x62/0xa6
[  385.698044]        kernel_init_freeable+0x97/0x193
[  385.698050]        kernel_init+0xa/0x100
[  385.698055]        ret_from_fork+0x27/0x40
[  385.698058]
               -> #2 (cpu_hotplug_lock.rw_sem){++++}:
[  385.698068]        cpus_read_lock+0x39/0xa0
[  385.698073]        apply_workqueue_attrs+0x12/0x50
[  385.698078]        __alloc_workqueue_key+0x1d8/0x4d8
[  385.698134]        i915_gem_init_userptr+0x5f/0x80 [i915]
[  385.698176]        i915_gem_init+0x7c/0x390 [i915]
[  385.698213]        i915_driver_load+0x99e/0x15c0 [i915]
[  385.698250]        i915_pci_probe+0x33/0x90 [i915]
[  385.698256]        pci_device_probe+0xa1/0x130
[  385.698262]        driver_probe_device+0x293/0x440
[  385.698267]        __driver_attach+0xde/0xe0
[  385.698272]        bus_for_each_dev+0x5c/0x90
[  385.698277]        bus_add_driver+0x16d/0x260
[  385.698282]        driver_register+0x57/0xc0
[  385.698287]        do_one_initcall+0x3e/0x160
[  385.698292]        do_init_module+0x5b/0x1fa
[  385.698297]        load_module+0x2374/0x2dc0
[  385.698302]        SyS_finit_module+0xaa/0xe0
[  385.698307]        entry_SYSCALL_64_fastpath+0x1c/0xb1
[  385.698311]
               -> #1 (&dev->struct_mutex){+.+.}:
[  385.698320]        __mutex_lock+0x86/0x9b0
[  385.698361]        i915_mutex_lock_interruptible+0x4c/0x130 [i915]
[  385.698403]        i915_gem_fault+0x206/0x760 [i915]
[  385.698409]        __do_fault+0x1a/0x70
[  385.698413]        __handle_mm_fault+0x7c4/0xdb0
[  385.698417]        handle_mm_fault+0x154/0x300
[  385.698440]        __do_page_fault+0x2d6/0x570
[  385.698445]        page_fault+0x22/0x30
[  385.698449]
               -> #0 (&mm->mmap_sem){++++}:
[  385.698459]        lock_acquire+0xaf/0x200
[  385.698464]        __might_fault+0x68/0x90
[  385.698470]        _copy_to_user+0x1e/0x70
[  385.698475]        perf_read+0x1aa/0x290
[  385.698480]        __vfs_read+0x23/0x120
[  385.698484]        vfs_read+0xa3/0x150
[  385.698488]        SyS_read+0x45/0xb0
[  385.698493]        entry_SYSCALL_64_fastpath+0x1c/0xb1
[  385.698497]
               other info that might help us debug this:

[  385.698505] Chain exists of:
                 &mm->mmap_sem --> pmus_lock --> &cpuctx_mutex

[  385.698517]  Possible unsafe locking scenario:

[  385.698522]        CPU0                    CPU1
[  385.698526]        ----                    ----
[  385.698529]   lock(&cpuctx_mutex);
[  385.698553]                                lock(pmus_lock);
[  385.698558]                                lock(&cpuctx_mutex);
[  385.698564]   lock(&mm->mmap_sem);
[  385.698568]
                *** DEADLOCK ***

[  385.698574] 1 lock held by perf_pmu/2631:
[  385.698578]  #0:  (&cpuctx_mutex){+.+.}, at: [<ffffffff8116fe8c>] perf_event_ctx_lock_nested+0xbc/0x1d0
[  385.698589]
               stack backtrace:
[  385.698595] CPU: 3 PID: 2631 Comm: perf_pmu Tainted: G     U          4.14.0-CI-Patchwork_7234+ #1
[  385.698602] Hardware name:                  /NUC6CAYB, BIOS AYAPLCEL.86A.0040.2017.0619.1722 06/19/2017
[  385.698609] Call Trace:
[  385.698615]  dump_stack+0x5f/0x86
[  385.698621]  print_circular_bug.isra.18+0x1d0/0x2c0
[  385.698627]  __lock_acquire+0x19c3/0x1b60
[  385.698634]  ? generic_exec_single+0x77/0xe0
[  385.698640]  ? lock_acquire+0xaf/0x200
[  385.698644]  lock_acquire+0xaf/0x200
[  385.698650]  ? __might_fault+0x3e/0x90
[  385.698655]  __might_fault+0x68/0x90
[  385.698660]  ? __might_fault+0x3e/0x90
[  385.698665]  _copy_to_user+0x1e/0x70
[  385.698670]  perf_read+0x1aa/0x290
[  385.698675]  __vfs_read+0x23/0x120
[  385.698682]  ? __fget+0x101/0x1f0
[  385.698686]  vfs_read+0xa3/0x150
[  385.698691]  SyS_read+0x45/0xb0
[  385.698696]  entry_SYSCALL_64_fastpath+0x1c/0xb1
[  385.698701] RIP: 0033:0x7ff1c46876ed
[  385.698705] RSP: 002b:00007fff13552f90 EFLAGS: 00000293 ORIG_RAX: 0000000000000000
[  385.698712] RAX: ffffffffffffffda RBX: ffffc90000647ff0 RCX: 00007ff1c46876ed
[  385.698718] RDX: 0000000000000010 RSI: 00007fff13552fa0 RDI: 0000000000000005
[  385.698723] RBP: 000056063d300580 R08: 0000000000000000 R09: 0000000000000060
[  385.698729] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000046
[  385.698734] R13: 00007fff13552c6f R14: 00007ff1c6279d00 R15: 00007ff1c6279a40

Testcase: igt/perf_pmu
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171122172621.16158-1-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

During selftesting intel_rotate_pages() is very, very verbose without
giving us any information. Suppress the noise.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171122145646.1859-1-chris@chris-wilson.co.ukReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

We may try to do a large kmalloc for the permutation array, falling back
to a smaller array/test if the first allocation fails. Since we are
intentionally trying a large allocation which may fail, pass __GFP_NOWARN.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103842Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171122120600.27025-1-chris@chris-wilson.co.ukReviewed-by: NMatthew Auld <matthew.auld@intel.com>

For clients like intel-gpu-overlay it is easier to read the
counters via the perf API than having to parse sysfs.
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/20171121181852.16128-9-tvrtko.ursulin@linux.intel.com

Will be used for exposing the PMU counters.

v2:
 * Move intel_runtime_pm_get/put to the callers. (Chris Wilson)
 * Restore full unit conversion precision.
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/20171121181852.16128-8-tvrtko.ursulin@linux.intel.com

For clients like intel-gpu-overlay it is easier to read the
count via the perf API than having to parse /proc.
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/20171121181852.16128-7-tvrtko.ursulin@linux.intel.com

We can use engine busy stats instead of the sampling timer for
better accuracy.

By doing this we replace the stohastic sampling with busyness
metric derived directly from engine activity. This is context
switch interrupt driven, so as accurate as we can get from
software tracking.

As a secondary benefit, we can also not run the sampling timer
in cases only busyness metric is enabled.

v2: Rebase.
v3:
 * Rebase, comments.
 * Leave engine busyness controls out of workers.
v4: Checkpatch cleanup.
v5: Added comment to pmu_needs_timer change.
v6:
 * Rebase.
 * Fix style of some comments. (Chris Wilson)
v7: Rebase and commit message update. (Chris Wilson)
v8: Add delayed stats disabling to improve accuracy in face of
    CPU hotplug events.
v9: Rebase.
v10: Rebase - i915_modparams.enable_execlists removal.
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/20171121181852.16128-6-tvrtko.ursulin@linux.intel.com

Track total time requests have been executing on the hardware.

We add new kernel API to allow software tracking of time GPU
engines are spending executing requests.

Both per-engine and global API is added with the latter also
being exported for use by external users.

v2:
 * Squashed with the internal API.
 * Dropped static key.
 * Made per-engine.
 * Store time in monotonic ktime.

v3: Moved stats clearing to disable.

v4:
 * Comments.
 * Don't export the API just yet.

v5: Whitespace cleanup.

v6:
 * Rename ref to active.
 * Drop engine aggregate stats for now.
 * Account initial busy period after enabling stats.

v7:
 * Rebase.

v8:
 * Move context in notification after the notifier. (Chris Wilson)

v9:

In cases where stats tracking is getting disabled while there is
an active context on an engine, add up the current value to the
total. This also implies we don't clear the total when tracking
is disabled any longer. There is no real need to do so because
we define the stats as relative while enabled, meaning
comparison between two samples while tracking is enabled is the
valid usage. However, when busy stats will later be plugged into
the perf PMU API, it is beneficial to not reset the total, since
the PMU core likes to do some counter disable/enable cycles on
startup, and while doing so during a single long context
executing on an engine we would lose some accuracy and so make
unit testing more difficult than needs to be.

v10:
 * Fix accounting for preemption.

v11:
 * Rebase for i915_modparams.enable_execlists removal.
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/20171121181852.16128-5-tvrtko.ursulin@linux.intel.com

No functional change just something which will be handy in the
following patch.
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/20171121181852.16128-4-tvrtko.ursulin@linux.intel.com

If only a subset of events is enabled we can afford to suspend
the sampling timer when the GPU is idle and so save some cycles
and power.

v2: Rebase and limit timer even more.
v3: Rebase.
v4: Rebase.
v5: Skip action if perf PMU failed to register.
v6: Checkpatch cleanup.
v7:
 * Add a common helper to start the timer if needed. (Chris Wilson)
 * Add comment explaining bitwise logic in pmu_needs_timer.
v8: Fix some comments styles. (Chris Wilson)
v9: Rebase.
v10: Move function declarations to i915_pmu.h.
v11: Rename functions to i915_pmu_gt_(un)parked. (Chris Wilson)
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/20171121181852.16128-3-tvrtko.ursulin@linux.intel.com

From: Chris Wilson <chris@chris-wilson.co.uk>
From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
From: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>

The first goal is to be able to measure GPU (and invidual ring) busyness
without having to poll registers from userspace. (Which not only incurs
holding the forcewake lock indefinitely, perturbing the system, but also
runs the risk of hanging the machine.) As an alternative we can use the
perf event counter interface to sample the ring registers periodically
and send those results to userspace.

Functionality we are exporting to userspace is via the existing perf PMU
API and can be exercised via the existing tools. For example:

  perf stat -a -e i915/rcs0-busy/ -I 1000

Will print the render engine busynnes once per second. All the performance
counters can be enumerated (perf list) and have their unit of measure
correctly reported in sysfs.

v1-v2 (Chris Wilson):

v2: Use a common timer for the ring sampling.

v3: (Tvrtko Ursulin)
 * Decouple uAPI from i915 engine ids.
 * Complete uAPI defines.
 * Refactor some code to helpers for clarity.
 * Skip sampling disabled engines.
 * Expose counters in sysfs.
 * Pass in fake regs to avoid null ptr deref in perf core.
 * Convert to class/instance uAPI.
 * Use shared driver code for rc6 residency, power and frequency.

v4: (Dmitry Rogozhkin)
 * Register PMU with .task_ctx_nr=perf_invalid_context
 * Expose cpumask for the PMU with the single CPU in the mask
 * Properly support pmu->stop(): it should call pmu->read()
 * Properly support pmu->del(): it should call stop(event, PERF_EF_UPDATE)
 * Introduce refcounting of event subscriptions.
 * Make pmu.busy_stats a refcounter to avoid busy stats going away
   with some deleted event.
 * Expose cpumask for i915 PMU to avoid multiple events creation of
   the same type followed by counter aggregation by perf-stat.
 * Track CPUs getting online/offline to migrate perf context. If (likely)
   cpumask will initially set CPU0, CONFIG_BOOTPARAM_HOTPLUG_CPU0 will be
   needed to see effect of CPU status tracking.
 * End result is that only global events are supported and perf stat
   works correctly.
 * Deny perf driver level sampling - it is prohibited for uncore PMU.

v5: (Tvrtko Ursulin)

 * Don't hardcode number of engine samplers.
 * Rewrite event ref-counting for correctness and simplicity.
 * Store initial counter value when starting already enabled events
   to correctly report values to all listeners.
 * Fix RC6 residency readout.
 * Comments, GPL header.

v6:
 * Add missing entry to v4 changelog.
 * Fix accounting in CPU hotplug case by copying the approach from
   arch/x86/events/intel/cstate.c. (Dmitry Rogozhkin)

v7:
 * Log failure message only on failure.
 * Remove CPU hotplug notification state on unregister.

v8:
 * Fix error unwind on failed registration.
 * Checkpatch cleanup.

v9:
 * Drop the energy metric, it is available via intel_rapl_perf.
   (Ville Syrjälä)
 * Use HAS_RC6(p). (Chris Wilson)
 * Handle unsupported non-engine events. (Dmitry Rogozhkin)
 * Rebase for intel_rc6_residency_ns needing caller managed
   runtime pm.
 * Drop HAS_RC6 checks from the read callback since creating those
   events will be rejected at init time already.
 * Add counter units to sysfs so perf stat output is nicer.
 * Cleanup the attribute tables for brevity and readability.

v10:
 * Fixed queued accounting.

v11:
 * Move intel_engine_lookup_user to intel_engine_cs.c
 * Commit update. (Joonas Lahtinen)

v12:
 * More accurate sampling. (Chris Wilson)
 * Store and report frequency in MHz for better usability from
   perf stat.
 * Removed metrics: queued, interrupts, rc6 counters.
 * Sample engine busyness based on seqno difference only
   for less MMIO (and forcewake) on all platforms. (Chris Wilson)

v13:
 * Comment spelling, use mul_u32_u32 to work around potential GCC
   issue and somne code alignment changes. (Chris Wilson)

v14:
 * Rebase.

v15:
 * Rebase for RPS refactoring.

v16:
 * Use the dynamic slot in the CPU hotplug state machine so that we are
   free to setup our state as multi-instance. Previously we were re-using
   the CPUHP_AP_PERF_X86_UNCORE_ONLINE slot which is neither used as
   multi-instance, nor owned by our driver to start with.
 * Register the CPU hotplug handlers after the PMU, otherwise the callback
   will get called before the PMU is initialized which can end up in
   perf_pmu_migrate_context with an un-initialized base.
 * Added workaround for a probable bug in cpuhp core.

v17:
 * Remove workaround for the cpuhp bug.

v18:
 * Rebase for drm_i915_gem_engine_class getting upstream before us.

v19:
 * Rebase. (trivial)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NDmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171121181852.16128-2-tvrtko.ursulin@linux.intel.com

Code to be shared between debugfs and the PMU implementation.

v2: Checkpatch cleanup.
v3: Also consolidate i915_sysfs.c/gt_act_freq_mhz_show.
v4: Rebase.
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/20171121181852.16128-1-tvrtko.ursulin@linux.intel.com

Despite us reloading the module around every selftest, the lockclasses
persist and the chains used in selftesting may then dictate how we are
allowed to nest locks during runtime testing. As such we have to be just
as careful, and in particular it turns out we are not allowed to nest
dev->object_name_lock (drm_gem_handle_create) inside dev->struct_mutex.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103830Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171121110652.1107-1-chris@chris-wilson.co.ukReviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Check that the planes are in the state we expect them to be. For
now we can only check whether each plane is correctly enabled or
disabled. In the future we may want to expand the plane state
readout to support a more thorough verification.

v2: Verify all planes part of the state as long as at least
    one crtc is doing a modeset (Daniel)
v3: Fix typoes (James)

Cc: James Ausmus <james.ausmus@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Suggested-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NJames Ausmus <james.ausmus@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171117191917.11506-11-ville.syrjala@linux.intel.comSigned-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

Since we now have a ->get_hw_state() method for planes, let's use
that during the initial plane fb readout.

v2: s/plane/i9xx_plane/ etc. (James)

Cc: James Ausmus <james.ausmus@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Suggested-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NJames Ausmus <james.ausmus@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171117191917.11506-10-ville.syrjala@linux.intel.comSigned-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

Eliminate crtc->plane since it's pretty much a layering violation.
We can always get the plane via crtc->primary if we actually need it.

The only ugly thing left is plane_to_crtc_mapping[], but that's
still needed by the pre-g4x watermark code.

v2: Removed a misplaced comment change (Daniel)
v3: Rebase due to fbc crtc->y usage removal
v4: s/plane/i9xx_plane/ etc. (James)

Cc: James Ausmus <james.ausmus@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171117191917.11506-9-ville.syrjala@linux.intel.comSigned-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>

Stop using the old for_each_intel_plane_in_state() type iteration
macro and replace it with for_each_new_intel_plane_in_state().
And similarly replace drm_atomic_get_existing_crtc_state() with
intel_atomic_get_new_crtc_state(). Switch over to intel_ types
as well to make the code less cluttered.

v2: s/plane/i9xx_plane/ etc. (James)

Cc: James Ausmus <james.ausmus@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171117191917.11506-8-ville.syrjala@linux.intel.comSigned-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>