History log of /openbmc/linux/drivers/gpu/drm/i915/i915_sw_fence.c (Results 1 – 25 of 43)
Revision Date Author Comments
# 60d54a45 29-Aug-2024 Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drm/i915/fence: Mark debug_fence_free() with __maybe_unused

[ Upstream commit f99999536128b14b5d765a9982763b5134efdd79 ]

When debug_fence_free() is unused
(CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS=n)

drm/i915/fence: Mark debug_fence_free() with __maybe_unused

[ Upstream commit f99999536128b14b5d765a9982763b5134efdd79 ]

When debug_fence_free() is unused
(CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS=n), it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:

.../i915_sw_fence.c:118:20: error: unused function 'debug_fence_free' [-Werror,-Wunused-function]
118 | static inline void debug_fence_free(struct i915_sw_fence *fence)
| ^~~~~~~~~~~~~~~~

Fix this by marking debug_fence_free() with __maybe_unused.

See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
inline functions for W=1 build").

Fixes: fc1584059d6c ("drm/i915: Integrate i915_sw_fence with debugobjects")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240829155950.1141978-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit 8be4dce5ea6f2368cc25edc71989c4690fa66964)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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# a65ebba8 29-Aug-2024 Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drm/i915/fence: Mark debug_fence_init_onstack() with __maybe_unused

[ Upstream commit fcd9e8afd546f6ced378d078345a89bf346d065e ]

When debug_fence_init_onstack() is unused (CONFIG_DRM_I915_SELFTEST=

drm/i915/fence: Mark debug_fence_init_onstack() with __maybe_unused

[ Upstream commit fcd9e8afd546f6ced378d078345a89bf346d065e ]

When debug_fence_init_onstack() is unused (CONFIG_DRM_I915_SELFTEST=n),
it prevents kernel builds with clang, `make W=1` and CONFIG_WERROR=y:

.../i915_sw_fence.c:97:20: error: unused function 'debug_fence_init_onstack' [-Werror,-Wunused-function]
97 | static inline void debug_fence_init_onstack(struct i915_sw_fence *fence)
| ^~~~~~~~~~~~~~~~~~~~~~~~

Fix this by marking debug_fence_init_onstack() with __maybe_unused.

See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
inline functions for W=1 build").

Fixes: 214707fc2ce0 ("drm/i915/selftests: Wrap a timer into a i915_sw_fence")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240829155950.1141978-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit 5bf472058ffb43baf6a4cdfe1d7f58c4c194c688)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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# 292a089d 20-Dec-2022 Steven Rostedt (Google) <rostedt@goodmis.org>

treewide: Convert del_timer*() to timer_shutdown*()

Due to several bugs caused by timers being re-armed after they are
shutdown and just before they are freed, a new state of timers was added
called

treewide: Convert del_timer*() to timer_shutdown*()

Due to several bugs caused by timers being re-armed after they are
shutdown and just before they are freed, a new state of timers was added
called "shutdown". After a timer is set to this state, then it can no
longer be re-armed.

The following script was run to find all the trivial locations where
del_timer() or del_timer_sync() is called in the same function that the
object holding the timer is freed. It also ignores any locations where
the timer->function is modified between the del_timer*() and the free(),
as that is not considered a "trivial" case.

This was created by using a coccinelle script and the following
commands:

$ cat timer.cocci
@@
expression ptr, slab;
identifier timer, rfield;
@@
(
- del_timer(&ptr->timer);
+ timer_shutdown(&ptr->timer);
|
- del_timer_sync(&ptr->timer);
+ timer_shutdown_sync(&ptr->timer);
)
... when strict
when != ptr->timer
(
kfree_rcu(ptr, rfield);
|
kmem_cache_free(slab, ptr);
|
kfree(ptr);
)

$ spatch timer.cocci . > /tmp/t.patch
$ patch -p1 < /tmp/t.patch

Link: https://lore.kernel.org/lkml/20221123201306.823305113@linutronix.de/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Pavel Machek <pavel@ucw.cz> [ LED ]
Acked-by: Kalle Valo <kvalo@kernel.org> [ wireless ]
Acked-by: Paolo Abeni <pabeni@redhat.com> [ networking ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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# 8146d588 22-Sep-2022 Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>

drm/i915: Remove unused function parameter

The function parameter 'exclude' in funciton
i915_sw_fence_await_reservation() is not used.
Remove it.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.c

drm/i915: Remove unused function parameter

The function parameter 'exclude' in funciton
i915_sw_fence_await_reservation() is not used.
Remove it.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922213916.12112-1-niranjana.vishwanathapura@intel.com

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# 03e067bc 30-Aug-2022 Jani Nikula <jani.nikula@intel.com>

drm/i915/fence: replace BUG_ON() with BUILD_BUG_ON()

Avoid BUG_ON(). Since __i915_sw_fence_init() is always called via a
wrapper macro, we can replace it with a compile time BUILD_BUG_ON().

Reviewe

drm/i915/fence: replace BUG_ON() with BUILD_BUG_ON()

Avoid BUG_ON(). Since __i915_sw_fence_init() is always called via a
wrapper macro, we can replace it with a compile time BUILD_BUG_ON().

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220830093411.1511040-5-jani.nikula@intel.com

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# 7bc80a54 09-Nov-2021 Christian König <christian.koenig@amd.com>

dma-buf: add enum dma_resv_usage v4

This change adds the dma_resv_usage enum and allows us to specify why a
dma_resv object is queried for its containing fences.

Additional to that a dma_resv_usage

dma-buf: add enum dma_resv_usage v4

This change adds the dma_resv_usage enum and allows us to specify why a
dma_resv object is queried for its containing fences.

Additional to that a dma_resv_usage_rw() helper function is added to aid
retrieving the fences for a read or write userspace submission.

This is then deployed to the different query functions of the dma_resv
object and all of their users. When the write paratermer was previously
true we now use DMA_RESV_USAGE_WRITE and DMA_RESV_USAGE_READ otherwise.

v2: add KERNEL/OTHER in separate patch
v3: some kerneldoc suggestions by Daniel
v4: some more kerneldoc suggestions by Daniel, fix missing cases lost in
the rebase pointed out by Bas.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-2-christian.koenig@amd.com

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# 44505168 16-Nov-2021 Matthew Brost <matthew.brost@intel.com>

drm/i915: Drop stealing of bits from i915_sw_fence function pointer

Rather than stealing bits from i915_sw_fence function pointer use
separate fields for function pointer and flags. If using two dif

drm/i915: Drop stealing of bits from i915_sw_fence function pointer

Rather than stealing bits from i915_sw_fence function pointer use
separate fields for function pointer and flags. If using two different
fields, the 4 byte alignment for the i915_sw_fence function pointer can
also be dropped.

v2:
(CI)
- Set new function field rather than flags in __i915_sw_fence_init
v3:
(Tvrtko)
- Remove BUG_ON(!fence->flags) in reinit as that will now blow up
- Only define fence->flags if CONFIG_DRM_I915_SW_FENCE_CHECK_DAG is
defined
v4:
- Rebase, resend for CI

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211116194929.10211-1-matthew.brost@intel.com

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# 1b5bdf07 13-Sep-2021 Christian König <christian.koenig@amd.com>

drm/i915: use the new iterator in i915_sw_fence_await_reservation v3

Simplifying the code a bit.

v2: use dma_resv_for_each_fence instead, according to Tvrtko the lock is
held here anyway.
v3: b

drm/i915: use the new iterator in i915_sw_fence_await_reservation v3

Simplifying the code a bit.

v2: use dma_resv_for_each_fence instead, according to Tvrtko the lock is
held here anyway.
v3: back to using dma_resv_for_each_fence_unlocked.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211116102431.198905-4-christian.koenig@amd.com

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# d3fae3b3 02-Jun-2021 Christian König <christian.koenig@amd.com>

dma-buf: drop the _rcu postfix on function names v3

The functions can be called both in _rcu context as well
as while holding the lock.

v2: add some kerneldoc as suggested by Daniel
v3: fix indenta

dma-buf: drop the _rcu postfix on function names v3

The functions can be called both in _rcu context as well
as while holding the lock.

v2: add some kerneldoc as suggested by Daniel
v3: fix indentation

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602111714.212426-7-christian.koenig@amd.com

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# 6b41323a 02-Jun-2021 Christian König <christian.koenig@amd.com>

dma-buf: rename dma_resv_get_excl_rcu to _unlocked

That describes much better what the function is doing here.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Jason Ekstrand

dma-buf: rename dma_resv_get_excl_rcu to _unlocked

That describes much better what the function is doing here.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602111714.212426-6-christian.koenig@amd.com

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# 460d02ba 16-Dec-2020 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Encode fence specific waitqueue behaviour into the wait.flags

Use the wait_queue_entry.flags to denote the special fence behaviour
(flattening continuations along fence chains, and for pro

drm/i915: Encode fence specific waitqueue behaviour into the wait.flags

Use the wait_queue_entry.flags to denote the special fence behaviour
(flattening continuations along fence chains, and for propagating
errors) rather than trying to detect ordinary waiters by their
functions.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201216165850.25030-1-chris@chris-wilson.co.uk

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# f9e62f31 14-Aug-2020 Stephen Boyd <swboyd@chromium.org>

treewide: Make all debug_obj_descriptors const

This should make it harder for the kernel to corrupt the debug object
descriptor, used to call functions to fixup state and track debug objects,
by mov

treewide: Make all debug_obj_descriptors const

This should make it harder for the kernel to corrupt the debug object
descriptor, used to call functions to fixup state and track debug objects,
by moving the structure to read-only memory.

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200815004027.2046113-3-swboyd@chromium.org

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# 20612303 28-Jul-2020 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Filter wake_flags passed to default_wake_function

(NOTE: This is the minimal backportable fix, a full fix is being
developed at https://patchwork.freedesktop.org/patch/388048/)

The flags

drm/i915: Filter wake_flags passed to default_wake_function

(NOTE: This is the minimal backportable fix, a full fix is being
developed at https://patchwork.freedesktop.org/patch/388048/)

The flags passed to the wait_entry.func are passed onwards to
try_to_wake_up(), which has a very particular interpretation for its
wake_flags. In particular, beyond the published WF_SYNC, it has a few
internal flags as well. Since we passed the fence->error down the chain
via the flags argument, these ended up in the default_wake_function
confusing the kernel/sched.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2110
Fixes: ef4688497512 ("drm/i915: Propagate fence errors")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: <stable@vger.kernel.org> # v5.4+
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200728152144.1100-1-chris@chris-wilson.co.uk
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[Joonas: Rebased and reordered into drm-intel-gt-next branch]
[Joonas: Added a note and link about more complete fix]
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
(cherry picked from commit f4b3c395540aa3d4f5a6275c5bdd83ab89034806)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

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# a80d7367 11-May-2020 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Tidy awaiting on dma-fences

Just tidy up the return handling for completed dma-fences. While it may
return errors for invalid fence, we already know that we have a good
fence and the only

drm/i915: Tidy awaiting on dma-fences

Just tidy up the return handling for completed dma-fences. While it may
return errors for invalid fence, we already know that we have a good
fence and the only error will be an already signaled fence.

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/20200511075722.13483-5-chris@chris-wilson.co.uk

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# 2386b492 19-Mar-2020 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Prefer '%ps' for printing function symbol names

%pS includes the offset, which is useful for return addresses but noise
when we are pretty printing a known (and expected) function entry po

drm/i915: Prefer '%ps' for printing function symbol names

%pS includes the offset, which is useful for return addresses but noise
when we are pretty printing a known (and expected) function entry point.

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/20200319091943.7815-1-chris@chris-wilson.co.uk

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# 42fb60de 11-Feb-2020 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915/gem: Don't leak non-persistent requests on changing engines

If we have a set of active engines marked as being non-persistent, we
lose track of those if the user replaces those engines with

drm/i915/gem: Don't leak non-persistent requests on changing engines

If we have a set of active engines marked as being non-persistent, we
lose track of those if the user replaces those engines with
I915_CONTEXT_PARAM_ENGINES. As part of our uABI contract is that
non-persistent requests are terminated if they are no longer being
tracked by the user's context (in order to prevent a lost request
causing an untracked and so unstoppable GPU hang), we need to apply the
same context cancellation upon changing engines.

v2: Track stale engines[] so we only reap at context closure.
v3: Tvrtko spotted races with closing contexts and set-engines, so add a
veneer of kill-everything paranoia to clean up after losing a race.

Fixes: a0e047156cde ("drm/i915/gem: Make context persistence optional")
Testcase: igt/gem_ctx_peristence/replace
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/20200211144831.1011498-1-chris@chris-wilson.co.uk

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# cbab8d87 06-Dec-2019 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Propagate errors on awaiting already signaled dma-fences

If we see an already signaled dma-fence that we want to await on, we skip
adding to the i915_sw_fence. However, we should pay atten

drm/i915: Propagate errors on awaiting already signaled dma-fences

If we see an already signaled dma-fence that we want to await on, we skip
adding to the i915_sw_fence. However, we should pay attention to whether
there was an error on that fence and if so propagate it for our future
request.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191206160428.1503343-3-chris@chris-wilson.co.uk

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# 67a3acaa 22-Nov-2019 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Use a ctor for TYPESAFE_BY_RCU i915_request

As we start peeking into requests for longer and longer, e.g.
incorporating use of spinlocks when only protected by an
rcu_read_lock(), we need

drm/i915: Use a ctor for TYPESAFE_BY_RCU i915_request

As we start peeking into requests for longer and longer, e.g.
incorporating use of spinlocks when only protected by an
rcu_read_lock(), we need to be careful in how we reset the request when
recycling and need to preserve any barriers that may still be in use as
the request is reset for reuse.

Quoting Linus Torvalds:

> If there is refcounting going on then why use SLAB_TYPESAFE_BY_RCU?

.. because the object can be accessed (by RCU) after the refcount has
gone down to zero, and the thing has been released.

That's the whole and only point of SLAB_TYPESAFE_BY_RCU.

That flag basically says:

"I may end up accessing this object *after* it has been free'd,
because there may be RCU lookups in flight"

This has nothing to do with constructors. It's ok if the object gets
reused as an object of the same type and does *not* get
re-initialized, because we're perfectly fine seeing old stale data.

What it guarantees is that the slab isn't shared with any other kind
of object, _and_ that the underlying pages are free'd after an RCU
quiescent period (so the pages aren't shared with another kind of
object either during an RCU walk).

And it doesn't necessarily have to have a constructor, because the
thing that a RCU walk will care about is

(a) guaranteed to be an object that *has* been on some RCU list (so
it's not a "new" object)

(b) the RCU walk needs to have logic to verify that it's still the
*same* object and hasn't been re-used as something else.

In contrast, a SLAB_TYPESAFE_BY_RCU memory gets free'd and re-used
immediately, but because it gets reused as the same kind of object,
the RCU walker can "know" what parts have meaning for re-use, in a way
it couidn't if the re-use was random.

That said, it *is* subtle, and people should be careful.

> So the re-use might initialize the fields lazily, not necessarily using a ctor.

If you have a well-defined refcount, and use "atomic_inc_not_zero()"
to guard the speculative RCU access section, and use
"atomic_dec_and_test()" in the freeing section, then you should be
safe wrt new allocations.

If you have a completely new allocation that has "random stale
content", you know that it cannot be on the RCU list, so there is no
speculative access that can ever see that random content.

So the only case you need to worry about is a re-use allocation, and
you know that the refcount will start out as zero even if you don't
have a constructor.

So you can think of the refcount itself as always having a zero
constructor, *BUT* you need to be careful with ordering.

In particular, whoever does the allocation needs to then set the
refcount to a non-zero value *after* it has initialized all the other
fields. And in particular, it needs to make sure that it uses the
proper memory ordering to do so.

NOTE! One thing to be very worried about is that re-initializing
whatever RCU lists means that now the RCU walker may be walking on the
wrong list so the walker may do the right thing for this particular
entry, but it may miss walking *other* entries. So then you can get
spurious lookup failures, because the RCU walker never walked all the
way to the end of the right list. That ends up being a much more
subtle bug.

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/20191122094924.629690-1-chris@chris-wilson.co.uk

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# ef468849 17-Aug-2019 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Propagate fence errors

Errors spread like wildfire, and must eventually be returned to the
user. They need to be captured and passed along the flow of fences,
infecting each in turn with t

drm/i915: Propagate fence errors

Errors spread like wildfire, and must eventually be returned to the
user. They need to be captured and passed along the flow of fences,
infecting each in turn with the existing error, until finally they fall
out of a user visible result.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190817232511.11391-1-chris@chris-wilson.co.uk

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# 52791eee 11-Aug-2019 Christian König <christian.koenig@amd.com>

dma-buf: rename reservation_object to dma_resv

Be more consistent with the naming of the other DMA-buf objects.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chris Wilson <

dma-buf: rename reservation_object to dma_resv

Be more consistent with the naming of the other DMA-buf objects.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/323401/

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# ea593dbb 22-Mar-2019 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Allow contexts to share a single timeline across all engines

Previously, our view has been always to run the engines independently
within a context. (Multiple engines happened before we ha

drm/i915: Allow contexts to share a single timeline across all engines

Previously, our view has been always to run the engines independently
within a context. (Multiple engines happened before we had contexts and
timelines, so they always operated independently and that behaviour
persisted into contexts.) However, at the user level the context often
represents a single timeline (e.g. GL contexts) and userspace must
ensure that the individual engines are serialised to present that
ordering to the client (or forgot about this detail entirely and hope no
one notices - a fair ploy if the client can only directly control one
engine themselves ;)

In the next patch, we will want to construct a set of engines that
operate as one, that have a single timeline interwoven between them, to
present a single virtual engine to the user. (They submit to the virtual
engine, then we decide which engine to execute on based.)

To that end, we want to be able to create contexts which have a single
timeline (fence context) shared between all engines, rather than multiple
timelines.

v2: Move the specialised timeline ordering to its own function.

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/20190322092325.5883-4-chris@chris-wilson.co.uk

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# e8861964 01-Mar-2019 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Use HW semaphores for inter-engine synchronisation on gen8+

Having introduced per-context seqno, we now have a means to identity
progress across the system without feel of rollback as befe

drm/i915: Use HW semaphores for inter-engine synchronisation on gen8+

Having introduced per-context seqno, we now have a means to identity
progress across the system without feel of rollback as befell the
global_seqno. That is we can program a MI_SEMAPHORE_WAIT operation in
advance of submission safe in the knowledge that our target seqno and
address is stable.

However, since we are telling the GPU to busy-spin on the target address
until it matches the signaling seqno, we only want to do so when we are
sure that busy-spin will be completed quickly. To achieve this we only
submit the request to HW once the signaler is itself executing (modulo
preemption causing us to wait longer), and we only do so for default and
above priority requests (so that idle priority tasks never themselves
hog the GPU waiting for others).

As might be reasonably expected, HW semaphores excel in inter-engine
synchronisation microbenchmarks (where the 3x reduced latency / increased
throughput more than offset the power cost of spinning on a second ring)
and have significant improvement (can be up to ~10%, most see no change)
for single clients that utilize multiple engines (typically media players
and transcoders), without regressing multiple clients that can saturate
the system or changing the power envelope dramatically.

v3: Drop the older NEQ branch, now we pin the signaler's HWSP anyway.
v4: Tell the world and include it as part of scheduler caps.

Testcase: igt/gem_exec_whisper
Testcase: igt/benchmarks/gem_wsim
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/20190301170901.8340-3-chris@chris-wilson.co.uk

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# b312d8ca 14-Nov-2018 Christian König <christian.koenig@amd.com>

dma-buf: make fence sequence numbers 64 bit v2

For a lot of use cases we need 64bit sequence numbers. Currently drivers
overload the dma_fence structure to store the additional bits.

Stop doing tha

dma-buf: make fence sequence numbers 64 bit v2

For a lot of use cases we need 64bit sequence numbers. Currently drivers
overload the dma_fence structure to store the additional bits.

Stop doing that and make the sequence number in the dma_fence always
64bit.

For compatibility with hardware which can do only 32bit sequences the
comparisons in __dma_fence_is_later only takes the lower 32bits as significant
when the upper 32bits are all zero.

v2: change the logic in __dma_fence_is_later

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Link: https://patchwork.freedesktop.org/patch/266927/

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# 635b3bc6 28-Nov-2018 Jonathan Gray <jsg@jsg.id.au>

drm/i915: change i915_sw_fence license to MIT

Change the license of the i915_sw_fence files to MIT matching
most of the other i915 files. This makes it possible to use them
in a new port of i915 to

drm/i915: change i915_sw_fence license to MIT

Change the license of the i915_sw_fence files to MIT matching
most of the other i915 files. This makes it possible to use them
in a new port of i915 to OpenBSD.

Besides some mechanical tree wide changes Chris Wilson is the sole
author of these files with Intel holding the copyright.

Intel's legal team have given permission to change the license according
to Joonas Lahtinen.

v2: expand commit message and note permission from Intel legal

Signed-off-by: Jonathan Gray <jsg@jsg.id.au>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20181129013051.17525-1-jsg@jsg.id.au

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# 5791bad4 14-Sep-2018 Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Include fence-hint for timeout warning

If an asynchronous wait on a foriegn fence, we print a warning
indicating which fence was not signaled. As i915_sw_fences become more
common, include

drm/i915: Include fence-hint for timeout warning

If an asynchronous wait on a foriegn fence, we print a warning
indicating which fence was not signaled. As i915_sw_fences become more
common, include the debug hint (the symbol-name of the target) to help
identify the waiter. E.g.

[ 31.968144] Asynchronous wait on fence sw_sync:gem_eio:1 timed out (hint:submit_notify [i915])

We also want to downgrade from a warning to a notice (normal but
significant condition) as the timeout is imposed and controlled by the
caller (i.e. it is deliberate) and can be provoked by userspace.

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/20180914124007.18790-1-chris@chris-wilson.co.uk

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