If client is smart or lucky enough to create a new context
after each hang, our context banning mechanism will never
catch up, and as a result of that it will be saved from
client banning. This can result in a never ending streak of
gpu hangs caused by bad or malicious client, preventing
access from other legit gpu clients.
Fix this by always incrementing per client ban score if
it hangs in short successions regardless of context ban
scoring. The exception are non bannable contexts. They remain
detached from client ban scoring mechanism.
v2: xchg timestamp, tidyup (Chris)
v3: comment, bannable & banned together (Chris)
Fixes: b083a0870c ("drm/i915: Add per client max context ban limit")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180615104429.31477-1-mika.kuoppala@linux.intel.com
(cherry picked from commit 14921f3cef)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Since we use i915_gem_find_active_request() from inside
intel_engine_dump() and may call that at any time, we do not guarantee
that the engine is paused nor that the signal kthreads and irq handler
are suspended, so we cannot assert that the breadcrumb doesn't advance
and that the irq hasn't happened on another CPU signaling the request we
believe to be idle.
The second assert removed (that request->engine == engine) remains
valid, but is now more rigorously checked during retirement.
Fixes: f636edb214 ("drm/i915: Make i915_engine_info pretty printer to standalone")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180529132922.6831-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
(cherry picked from commit cc7cc53435)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
When we process the outstanding requests upon banning a context, we need
to acquire both the engine and the client's timeline, nesting the locks.
This requires explicit markup as the two timelines are now of the same
class, since commit a89d1f921c ("drm/i915: Split i915_gem_timeline into
individual timelines").
Testcase: igt/gem_eio/banned
Fixes: a89d1f921c ("drm/i915: Split i915_gem_timeline into individual timelines")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180512084957.9829-1-chris@chris-wilson.co.uk
When called from process context tasklet_schedule() defers itself to
ksoftirqd. From experience this may cause unacceptable latencies of over
200ms in executing the submission tasklet, our goal is to reprioritise
the HW execution queue and trigger HW preemption immediately, so disable
bh over the call to schedule and force the tasklet to run afterwards if
scheduled.
v2: Keep rcu_read_lock() around for PREEMPT_RCU
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180507135731.10587-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
When userspace is passing around swapbuffers using DRI, we frequently
have to open and close the same object in the foreign address space.
This shows itself as the same object being rebound at roughly 30fps
(with a second object also being rebound at 30fps), which involves us
having to rewrite the page tables and maintain the drm_mm range manager
every time.
However, since the object still exists and it is only the local handle
that disappears, if we are lazy and do not unbind the VMA immediately
when the local user closes the object but defer it until the GPU is
idle, then we can reuse the same VMA binding. We still have to be
careful to mark the handle and lookup tables as closed to maintain the
uABI, just allowing the underlying VMA to be resurrected if the user is
able to access the same object from the same context again.
If the object itself is destroyed (neither userspace keeping a handle to
it), the VMA will be reaped immediately as usual.
In the future, this will be even more useful as instantiating a new VMA
for use on the GPU will become heavier. A nuisance indeed, so nip it in
the bud.
v2: s/__i915_vma_final_close/i915_vma_destroy/ etc.
v3: Leave a hint as to why we deferred the unbind on close.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180503195115.22309-1-chris@chris-wilson.co.uk
We need to move to a more flexible timeline that doesn't assume one
fence context per engine, and so allow for a single timeline to be used
across a combination of engines. This means that preallocating a fence
context per engine is now a hindrance, and so we want to introduce the
singular timeline. From the code perspective, this has the notable
advantage of clearing up a lot of mirky semantics and some clumsy
pointer chasing.
By splitting the timeline up into a single entity rather than an array
of per-engine timelines, we can realise the goal of the previous patch
of tracking the timeline alongside the ring.
v2: Tweak wait_for_idle to stop the compiling thinking that ret may be
uninitialised.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180502163839.3248-2-chris@chris-wilson.co.uk
In the future, we want to move a request between engines. To achieve
this, we first realise that we have two timelines in effect here. The
first runs through the GTT is required for ordering vma access, which is
tracked currently by engine. The second is implied by sequential
execution of commands inside the ringbuffer. This timeline is one that
maps to userspace's expectations when submitting requests (i.e. given the
same context, batch A is executed before batch B). As the rings's
timelines map to userspace and the GTT timeline an implementation
detail, move the timeline from the GTT into the ring itself (per-context
in logical-ring-contexts/execlists, or a global per-engine timeline for
the shared ringbuffers in legacy submission.
The two timelines are still assumed to be equivalent at the moment (no
migrating requests between engines yet) and so we can simply move from
one to the other without adding extra ordering.
v2: Reinforce that one isn't allowed to mix the engine execution
timeline with the client timeline from userspace (on the ring).
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180502163839.3248-1-chris@chris-wilson.co.uk
We don't need to track every ring for its lifetime as they are managed
by the contexts/engines. What we do want to track are the live rings so
that we can sporadically clean up requests if userspace falls behind. We
can simply restrict the gt->rings list to being only gt->live_rings.
v2: s/live/active/ for consistency with gt.active_requests
Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180430131503.5375-4-chris@chris-wilson.co.uk
In the next patch, rings are the central timeline as requests may jump
between engines. Therefore in the future as we retire in order along the
engine timeline, we may retire out-of-order within a ring (as the ring now
occurs along multiple engines), leading to much hilarity in miscomputing
the position of ring->head.
As an added bonus, retiring along the ring reduces the penalty of having
one execlists client do cleanup for another (old legacy submission
shares a ring between all clients). The downside is that slow and
irregular (off the critical path) process of cleaning up stale requests
after userspace becomes a modicum less efficient.
In the long run, it will become apparent that the ordered
ring->request_list matches the ring->timeline, a fun challenge for the
future will be unifying the two lists to avoid duplication!
v2: We need both engine-order and ring-order processing to maintain our
knowledge of where individual rings have completed upto as well as
knowing what was last executing on any engine. And finally by decoupling
retiring the contexts on the engine and the timelines along the rings,
we do have to keep a reference to the context on each request
(previously it was guaranteed by the context being pinned).
v3: Not just a reference to the context, but we need to keep it pinned
as we manipulate the rings; i.e. we need a pin for both the manipulation
of the engine state during its retirements, and a separate pin for the
manipulation of the ring state.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180430131503.5375-3-chris@chris-wilson.co.uk
Make life easier in upcoming patches by moving the context_pin and
context_unpin vfuncs into inline helpers.
v2: Fixup mock_engine to mark the context as pinned on use.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180430131503.5375-2-chris@chris-wilson.co.uk
The majority of the engine state dumping is too voluminous to be useful
outside of a controlled setup, though a few do accompany severe errors.
Keep the debug dumps next to the errors, but hide the others behind a CI
compile flag. This becomes more useful when adding more dumps to latency
sensitive paths.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180426103219.22181-1-chris@chris-wilson.co.uk
Today we only want to pass along the priority to engine->schedule(), but
in the future we want to have much more control over the various aspects
of the GPU during a context's execution, for example controlling the
frequency allowed. As we need an ever growing number of parameters for
scheduling, move those into a struct for convenience.
v2: Move the anonymous struct into its own function for legibility and
ye olde gcc.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180418184052.7129-3-chris@chris-wilson.co.uk
There are different kind of workarounds (those that modify registers that
live in the context image, those that modify global registers, those that
whitelist registers, etc...) and they have different requirements in terms
of where they are applied and how. Also, by splitting them apart, it should
be easier to decide where a new workaround should go.
v2:
- Add multiple MISSING_CASE
- Rebased
v3:
- Rename mmio_workarounds to gt_workarounds (Chris, Mika)
- Create empty placeholders for BDW and CHV GT WAs
- Rebased
v4: Rebased
v5:
- Rebased
- FORCE_TO_NONPRIV register exists since BDW, so make a path
for it to achieve universality, even if empty (Chris)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[ickle: appease checkpatch]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/1523376767-18480-2-git-send-email-oscar.mateo@intel.com
Resetting the GPU doesn't affect the RPS/RC6 state, so we can stop
forcibly reloading the registers.
Ville suggested this many moons ago, I said at that time that sanitizing
was no harm and meant that our bookkeeping was kept consistent with the
HW. However, in a forthcoming series, we want to split rps/rc6 GT
powermanagement and one of the key simplifications is the control of
when we enable it. Performing a crude sanitize in the middle of
i915_gem_reset() is then a huge wart.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180410133354.13425-1-chris@chris-wilson.co.uk
Currently, we rely on inspecting the hangcheck state from within the
i915_reset() routines to determine which engines were guilty of the
hang. This is problematic for cases where we want to run
i915_handle_error() and call i915_reset() independently of hangcheck.
Instead of relying on the indirect parameter passing, turn it into an
explicit parameter providing the set of stalled engines which then are
treated as guilty until proven innocent.
While we are removing the implicit stalled parameter, also make the
reason into an explicit parameter to i915_reset(). We still need a
back-channel for i915_handle_error() to hand over the task to the locked
waiter, but let's keep that its own channel rather than incriminate
another.
This leaves stalled/seqno as being private to hangcheck, with no more
nefarious snooping by reset, be it whole-device or per-engine. \o/
The only real issue now is that this makes it crystal clear that we
don't actually do any testing of hangcheck per se in
drv_selftest/live_hangcheck, merely of resets!
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180406220354.18911-2-chris@chris-wilson.co.uk
If we are resetting just one engine, we know it has stalled. So we can
pass the stalled parameter directly to i915_gem_reset_engine(), which
alleviates the necessity to poke at the generic engine->hangcheck.stalled
magic variable, leaving that under control of hangcheck as its name
implies. Other than simplifying by removing the indirect parameter along
this path, this allows us to introduce new reset mechanisms that run
independently of hangcheck.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180406220354.18911-1-chris@chris-wilson.co.uk
We will want to park GEM before disengaging the drive^W^W^W unwedging.
Since we already do the work for idling, expose the guts as a new
function that we can then reuse.
v2: Just skip if already parked; makes it more forgiving to use by
future callers.
v3: Extract mark_busy, rename it to i915_gem_unpark and place it next to
i915_gem_park so that we can evaluate it for symmetry more easily.
Calling GEM from inside i915_request looks to be a bit of a layering
violation, for the moment I am imaging them as being notify_cb.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> #v1
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180406155144.27791-1-chris@chris-wilson.co.uk
In upcoming patch, we want to perform more actions in early
initialization of the uC. This reordering will help resolve
new dependencies that will be introduced by future patch.
v2: s/i915_gem_load_init/i915_gem_init_early (Chris)
v3: s/i915_gem_load_cleanup/i915_gem_cleanup_early (Michal)
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180323123451.59244-1-michal.wajdeczko@intel.com
If we fail to reset the GPU, we declare the machine wedged. However, the
GPU may well still be running in the background with an in-flight
request. So despite our efforts in cleaning up the request queue and
faking the breadcrumb in the HWSP, the GPU may eventually write the
in-flght seqno there breaking all of our assumptions and throwing the
driver into a deep turmoil, wedging beyond wedged.
To avoid this we ideally want to reset the GPU. Since that has already
failed, make sure the rings have the stop bit set instead. This is part
of the normal GPU reset sequence, but that is actually disabled by
igt/gem_eio to force the wedged state. If we assume the worst, we must
poke at the bit again before we give up.
v2: Move the intel_gpu_reset() from set-wedged in the reset error path
into i915_gem_set_wedged() itself. Even if the reset fails (e.g. if it is
disabled by gem_eio), it still tries to make sure the engines are
stopped. For i915_gem_set_wedged() callers from outside of i915_reset(),
this should make sure the GPU is disabled while the driver is marked as
being wedged.
Testcase: igt/gem_eio
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180315151015.22741-1-chris@chris-wilson.co.uk
We still have an odd race with wedging/unwedging as shown by igt/gem_eio
that defies expectations. Add some more trace_printks to try and
visualize the flow over the precipice.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180315131451.4060-1-chris@chris-wilson.co.uk
GuC WOPCM registers are write-once registers. Current driver code accesses
these registers without checking the accessibility to these registers which
will lead to unpredictable driver behaviors if these registers were touch
by other components (such as faulty BIOS code).
This patch moves the GuC WOPCM registers updating code into intel_wopcm.c
and adds check before and after the update to GuC WOPCM registers so that
we can make sure the driver is in a known state after writing to these
write-once registers.
v6:
- Made sure module reloading won't bug the kernel while doing
locking status checking
v7:
- Fixed patch format issues
v8:
- Fixed coding style issue on register lock bit macro definition (Sagar)
v9:
- Avoided to use redundant !! to cast uint to bool (Chris)
- Return error code instead of GEM_BUG_ON for locked with invalid register
values case (Sagar)
- Updated guc_wopcm_hw_init to use guc_wopcm as first parameter (Michal)
- Added code to set and validate the HuC_LOADING_AGENT_GUC bit in GuC
WOPCM offset register based on the presence of HuC firmware (Michal)
- Use bit fields instead of macros for GuC WOPCM flags (Michal)
v10:
- Refined variable names, removed redundant comments (Joonas)
- Introduced lockable_reg to handle the write once register write and
propagate the write error to caller (Joonas)
- Used lockable_reg abstraction to avoid locking bit check on generic
i915_reg_t (Michal)
- Added log message for error paths (Michal)
- Removed hw_updated flag and only relies on real hardware status
v11:
- Replaced lockable_reg with simplified function (Michal)
- Used new macros for locking bits of WOPCM size/offset registers instead
of using BIT(0) directly (Michal)
- use intel_wopcm_init_hw() called from intel_gem_init_hw() to do GuC
WOPCM register setup instead of calling from intel_uc_init_hw() (Michal)
v12:
- Updated function kernel-doc to align with code changes (Michal)
- Updated code to use wopcm pointer directly (Michal)
v13:
- Updated the ordering of s-o-b/cc/r-b tags (Sagar)
BSpec: 10875, 10833
Signed-off-by: Jackie Li <yaodong.li@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com> (v11)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v12)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1520987574-19351-5-git-send-email-yaodong.li@intel.com
Hardware may have specific restrictions on GuC WOPCM offset and size. On
Gen9, the value of the GuC WOPCM size register needs to be larger than the
value of GuC WOPCM offset register + a Gen9 specific offset (144KB) for
reserved GuC WOPCM. Fail to enforce such a restriction on GuC WOPCM size
will lead to GuC firmware execution failures. On the other hand, with
current static GuC WOPCM offset and size values (512KB for both offset and
size), the GuC WOPCM size verification will fail on Gen9 even if it can be
fixed by lowering the GuC WOPCM offset by calculating its value based on
HuC firmware size (which is likely less than 200KB on Gen9), so that we can
have a GuC WOPCM size value which is large enough to pass the GuC WOPCM
size check.
This patch updates the reserved GuC WOPCM size for RC6 context on Gen9 to
24KB to strictly align with the Gen9 GuC WOPCM layout. It also adds support
to verify the GuC WOPCM size aganist the Gen9 hardware restrictions. To
meet all above requirements, let's provide dynamic partitioning of the
WOPCM that will be based on platform specific HuC/GuC firmware sizes.
v2:
- Removed intel_wopcm_init (Ville/Sagar/Joonas)
- Renamed and Moved the intel_wopcm_partition into intel_guc (Sagar)
- Removed unnecessary function calls (Joonas)
- Init GuC WOPCM partition as soon as firmware fetching is completed
v3:
- Fixed indentation issues (Chris)
- Removed layering violation code (Chris/Michal)
- Created separat files for GuC wopcm code (Michal)
- Used inline function to avoid code duplication (Michal)
v4:
- Preset the GuC WOPCM top during early GuC init (Chris)
- Fail intel_uc_init_hw() as soon as GuC WOPCM partitioning failed
v5:
- Moved GuC DMA WOPCM register updating code into intel_wopcm.c
- Took care of the locking status before writing to GuC DMA
Write-Once registers. (Joonas)
v6:
- Made sure the GuC WOPCM size to be multiple of 4K (4K aligned)
v8:
- Updated comments and fixed naming issues (Sagar/Joonas)
- Updated commit message to include more description about the hardware
restriction on GuC WOPCM size (Sagar)
v9:
- Minor changes variable names and code comments (Sagar)
- Added detailed GuC WOPCM layout drawing (Sagar/Michal)
- Refined macro definitions to be reader friendly (Michal)
- Removed redundent check to valid flag (Michal)
- Unified first parameter for exported GuC WOPCM functions (Michal)
- Refined the name and parameter list of hardware restriction checking
functions (Michal)
v10:
- Used shorter function name for internal functions (Joonas)
- Moved init-ealry function into c file (Joonas)
- Consolidated and removed redundant size checks (Joonas/Michal)
- Removed unnecessary unlikely() from code which is only called once
during boot (Joonas)
- More fixes to kernel-doc format and content (Michal)
- Avoided the use of PAGE_MASK for 4K pages (Michal)
- Added error log messages to error paths (Michal)
v11:
- Replaced intel_guc_wopcm with more generic intel_wopcm and attached
intel_wopcm to drm_i915_private instead intel_guc (Michal)
- dynamic calculation of GuC non-wopcm memory start (a.k.a WOPCM Top
offset from GuC WOPCM base) (Michal)
- Moved WOPCM marco definitions into .c source file (Michal)
- Exported WOPCM layout diagram as kernel-doc (Michal)
v12:
- Updated naming, function kernel-doc to align with new changes (Michal)
v13:
- Updated the ordering of s-o-b/cc/r-b tags (Sagar)
- Corrected one tense error in comment (Sagar)
- Corrected typos and removed spurious comments (Joonas)
Bspec: 12690
Signed-off-by: Jackie Li <yaodong.li@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: John Spotswood <john.a.spotswood@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com> (v8)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v9)
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com> (v11)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v12)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1520987574-19351-2-git-send-email-yaodong.li@intel.com
If we timeout waiting for the GPU to idle, something went seriously
wrong. We currently dump the engine state, but we can also dump the
ftrace buffer showing our last operations (when available).
In passing, note that since commit 559e040f1f ("drm/i915: Show the GPU
state when declaring wedged", we now show the engine state twice, once
in detecting the failed idle and then again on declaring wedged.
v2: ftrace_dump() takes a parameter specifying whether to dump all cpu
buffers or the local cpu's.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180309101114.1138-1-chris@chris-wilson.co.uk
i915_gem_obj_pin_to_display() calls frontbuffer_flush with origin set to
DIRTYFB. The callers however are at a vantage point to decide if hardware
frontbuffer tracking can do the flush for us. For example, legacy cursor
updates, like flips, write to MMIO registers, which then triggers PSR flush
by the hardware. Moving frontbuffer_flush out will enable us to skip a
software initiated flush by setting origin to FLIP. Thanks to Chris for the
idea.
v2:
Rebased due to Ville adding intel_plane_pin_fb().
Minor code reordering as fb_obj_flush doesn't need struct_mutex (Chris)
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307033420.3086-1-dhinakaran.pandiyan@intel.com
Instead of dancing around uC on reset/suspend/resume scenarios,
explicitly sanitize uC when we sanitize GEM to force uC reload
and start from known beginning.
v2: don't forget about reset path (Daniele)
sanitize uc before gem initiated full reset (Daniele)
v3: drop redundant disable_communication in init_hw (Daniele)
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180312130308.22952-3-michal.wajdeczko@intel.com
tasklet_kill() will spin waiting for the current tasklet to be executed.
However, if tasklet_disable() has been called, then the tasklet is never
executed but permanently put back onto the runlist until
tasklet_enable() is called. Ergo, we cannot use tasklet_kill() inside a
disable/enable pair. This is the case when we call set-wedge from inside
i915_reset(), and another request was submitted to us concurrent to the
reset.
Fixes: 963ddd63c3 ("drm/i915: Suspend submission tasklets around wedging")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307134226.25492-6-chris@chris-wilson.co.uk
Similar to the staging around handling of engine->submit_request, we
need to stop adding to the execlists->queue prior to calling
engine->cancel_requests. cancel_requests will move requests from the
queue onto the timeline, so if we add a request onto the queue after that
point, it will be lost.
Fixes: af7a8ffad9 ("drm/i915: Use rcu instead of stop_machine in set_wedged")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307134226.25492-5-chris@chris-wilson.co.uk
Before we reset the GPU after marking the device as wedged, we wait for
all the remaining requests to be completed (and marked as EIO).
Afterwards, we should flush the request lists so the next batch start
with the driver in an idle state.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307134226.25492-1-chris@chris-wilson.co.uk
Currently, we only allow ourselves to prune the fences so long as
all the waits completed (i.e. all the fences we checked were signaled),
and that the reservation snapshot did not change across the wait.
However, if we only waited for a subset of the reservation object, i.e.
just waiting for the last writer to complete as opposed to all readers
as well, then we would erroneously conclude we could prune the fences as
indeed although all of our waits were successful, they did not represent
the totality of the reservation object.
v2: We only need to check the shared fences due to construction (i.e.
all of the shared fences will be later than the exclusive fence, if
any).
Fixes: e54ca97747 ("drm/i915: Remove completed fences after a wait")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307171303.29466-1-chris@chris-wilson.co.uk
We want to use higher level 'uc' functions as the main entry points to
the GuC/HuC code to hide some details and keep code layered.
While here, move call to disable_guc_interrupts after sending suspend
action to the GuC to allow it work also with CTB as comm mechanism.
v2: update commit msg (Sagar)
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180302111550.21328-1-michal.wajdeczko@intel.com
Now that we can pass arbitrary commands into the base __wait_for()
macro, we can reimplement the open-coded wait-for inside
i915_gem_idle_work_handler() using the new macro. This means that instead
of using ktime, we now use jiffies, and benefit from the exponential sleep
backoff that allows a fast response if the HW settles quickly.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180301103338.5380-1-chris@chris-wilson.co.uk
We want to de-emphasize the link between the request (dependency,
execution and fence tracking) from GEM and so rename the struct from
drm_i915_gem_request to i915_request. That is we may implement the GEM
user interface on top of requests, but they are an abstraction for
tracking execution rather than an implementation detail of GEM. (Since
they are not tied to HW, we keep the i915 prefix as opposed to intel.)
In short, the spatch:
@@
@@
- struct drm_i915_gem_request
+ struct i915_request
A corollary to contracting the type name, we also harmonise on using
'rq' shorthand for local variables where space if of the essence and
repetition makes 'request' unwieldy. For globals and struct members,
'request' is still much preferred for its clarity.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180221095636.6649-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Acked-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
We cannot simply use !view as shorthand for all normal GGTT views as a
few callers will always populate a i915_ggtt_view struct and set the
type to NORMAL instead. So check for (!view || view->type == NORMAL)
inside i915_gem_object_ggtt_pin().
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180220134208.24988-1-chris@chris-wilson.co.uk
During igt, we frequently call into the driver to reset both HW and
driver state (idling the device, waiting for it to become idle and
freeing off old objects) to ensure that we start each test/subtest/pass
from known state. This process incurs an RCU barrier or two to ensure
that any such pending frees are indeed flushed before we return.
However, unconditionally waiting on the RCU barrier adds needless delay
to many callers, which adds up to several seconds when repeated thousands
of times. We can skip the rcu_barrier() if by tracking how many outstanding
frees we have, we know there are none.
The same path is used along suspend, where we may be able to save the
unconditional RCU barrier.
To put it into perspective with a completely meaningless
microbenchmark, igt/gem_sync/idle is improved from 50ms to 30us on bdw.
v2: Remove the extra synchronize_rcu() inside i915_drop_caches_set()
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180219220631.25001-1-chris@chris-wilson.co.uk
i915 is the only driver using those fields in the drm_gem_object
structure, so they only waste memory for all other drivers.
Move the fields into drm_i915_gem_object instead and patch the i915 code
with the following sed commands:
sed -i "s/obj->base.read_domains/obj->read_domains/g" drivers/gpu/drm/i915/*.c drivers/gpu/drm/i915/*/*.c
sed -i "s/obj->base.write_domain/obj->write_domain/g" drivers/gpu/drm/i915/*.c drivers/gpu/drm/i915/*/*.c
Change is only compile tested.
v2: move fields around as suggested by Chris.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180216124338.9087-1-christian.koenig@amd.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reduce the window of opportunity for set-wedged being called
concurrently with reset (after i915_reset() has performed the
i915_gem_unset_wedged()) by moving the set_bit(I915_WEDGED) to before we
complete the inflight requests. When i915_reset() is being blocked on a
request, such completion may allow it to start and beginning resetting
the GPU before i915_gem_set_wedged() has finished (and so before
set-wedge will have marked the device as wedged). As such,
i915_gem_init_hw() may see a wedged device even from inside
i915_reset().
References: 36703e79a9 ("drm/i915: Break modeset deadlocks on reset")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180207151350.20883-1-chris@chris-wilson.co.uk
Since commit 5896a5c8c9 (drm/i915: Always stop the rings before a
missing GPU reset) we attempt to stop the engines during gem_sanitize
even if reset=0 and nothing bad happened on the gpu.
The specs says that the STOP_RINGS bit needs to be cleared to resume
normal operation, but for some reason the value of the bit seems to be
changing without us writing to it (maybe rc6 entry/exit?), so normal
operation resumes correctly. However, it still feels incorrect to stop
the engines if there hasn't been any issue so skip the whole reset
call in gem_sanitize if i915.reset=0
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180207212440.13438-1-daniele.ceraolospurio@intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Rather than having the high level ioctl interface guess the underlying
implementation details, having the implementation declare what
capabilities it exports. We define an intel_driver_caps, similar to the
intel_device_info, which instead of trying to describe the HW gives
details on what the driver itself supports. This is then populated by
the engine backend for the new scheduler capability field for use
elsewhere.
v2: Use caps.scheduler for validating CONTEXT_PARAM_SET_PRIORITY (Mika)
One less assumption of engine[RCS] \o/
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tomasz Lis <tomasz.lis@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Tomasz Lis <tomasz.lis@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180207210544.26351-2-chris@chris-wilson.co.uk
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
On blb and pnv, we are seeing sporadic
i915 0000:00:02.0: Resetting chip after gpu hang
[drm:intel_gpu_reset [i915]] rcs0: timed out on STOP_RING
[drm:i915_reset [i915]] *ERROR* Failed hw init on reset -5
which notably lack the actual root cause of the error. Ostensibly it
should be the init_ring_common() that failed, but it's error paths are
covered by DRM_ERROR.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180207111545.17078-1-chris@chris-wilson.co.uk
Since commit 7b6da818d8 ("drm/i915: Restore the kernel context after a
GPU reset on an idle engine") we submit a request following the engine
reset. The intent is that we don't submit a request if the engine is
busy (as it will restart active by itself) but we only checked to see if
there were remaining requests in flight on the hardware and skipped
checking to see if there were any ready requests that would be
immediately submitted on restart (the same time as our new request would
be). Having convinced the engine to appear idle in the previous patch,
we can use intel_engine_is_idle() as a better test to only submit a new
request if there are no pending requests.
As it happens, this is tripping up igt/drv_selftest/live_hangcheck in CI
as we overfill the kernel_context ringbuffer trigger an infinite
recursion from within the reset.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104786
References: 7b6da818d8 ("drm/i915: Restore the kernel context after a GPU reset on an idle engine")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180205152431.12163-4-chris@chris-wilson.co.uk
During testing, we trigger a lot of resets on an unbannable context
leading to massive amounts of irrelevant debug spam. Remove the
ban_score accounting and message for the unbannable context so that we
improve the signal:noise in the log messages for when the unexpected
occurs.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180205092201.19476-7-chris@chris-wilson.co.uk
Dump each engine state when i915_gem_set_wedged() is called to give us
some more clues as to why we had to terminate the GPU.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180205092201.19476-5-chris@chris-wilson.co.uk
The headers should be on a separate line for consistency, so add the
missing trailing newline in a few intel_engine_dump() callers.
Reported-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180205100618.11001-1-chris@chris-wilson.co.uk
Previously, we relied on only running the hangcheck while somebody was
waiting on the GPU, in order to minimise the amount of time hangcheck
had to run. (If nobody was watching the GPU, nobody would notice if the
GPU wasn't responding -- eventually somebody would care and so kick
hangcheck into action.) However, this falls apart from around commit
4680816be3 ("drm/i915: Wait first for submission, before waiting for
request completion"), as not all waiters declare themselves to hangcheck
and so we could switch off hangcheck and miss GPU hangs even when
waiting under the struct_mutex.
If we enable hangcheck from the first request submission, and let it run
until the GPU is idle again, we forgo all the complexity involved with
only enabling around waiters. We just have to remember to be careful that
we do not declare a GPU hang when idly waiting for the next request to
be come ready, as we will run hangcheck continuously even when the
engines are stalled waiting for external events. This should be true
already as we should only be tracking requests submitted to hardware for
execution as an indicator that the engine is busy.
Fixes: 4680816be3 ("drm/i915: Wait first for submission, before waiting for request completion"
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104840
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180129144104.3921-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
When we finally decide the gpu is idle, that is a good time to shrink
our kmem_caches.
v3: Defer until an rcu grace period after we idle.
v4: Think about epoch wraparound and how likely that is.
v5: Use I915_EPOCH_INVALID magic.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180124113608.14909-2-chris@chris-wilson.co.uk
Watching a light workload on Baytrail (running glxgears and a 1080p
decode), instead of the system remaining at low frequency, the glxgears
would regularly trigger waitboosting after which it would have to spend
a few seconds throttling back down. In this case, the waitboosting is
counter productive as the minimal wait for glxgears doesn't prevent it
from functioning correctly and delivering frames on time. In this case,
glxgears happens to almost always be waiting on the current request,
which we already expect to complete quickly (see i915_spin_request) and
so avoiding the waitboost on the active request and spinning instead
provides the best latency without overcommitting to upclocking.
However, if the system falls behind we still force the waitboost.
Similarly, we will also trigger upclocking if we detect the system is
not delivering frames on time - again using a mechanism that tries to
detect a miss and not preemptively upclock.
v2: Also skip boosting for after missed vblank if the desired request is
already active.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Radoslaw Szwichtenberg <radoslaw.szwichtenberg@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180118131609.16574-1-chris@chris-wilson.co.uk