Due to the latency of the tasklet running from ksoftirqd, by the time we
process the execlist dequeue may be a long time behind the GPU. If the
request was completed when we ran reschedule, we will not have tweaked
its priority, but if it is still listed as being in-flight for dequeue
we will use it as a reference for the rest of the queue, including
requests from its own context which will now be at higher priority. This
can cause us to issue a preempt-to-idle request, even though the request
we want to preempt is already complete.
Reported-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180501122131.19435-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Previously, we just reset the ring register in the context image such
that we could skip over the broken batch and emit the closing
breadcrumb. However, on resume the context image and GPU state would be
reloaded, which may have been left in an inconsistent state by the
reset. The presumption was that at worst it would just cause another
reset and skip again until it recovered, however it seems just as likely
to cause an unrecoverable hang. Instead of risking loading an incomplete
context image, restore it back to the default state.
v2: Fix up off-by-one from including the ppHSWP in with the register
state.
v3: Use a ring local to compact a few lines.
v4: Beware setting the ring local before checking for a NULL request.
References: https://bugs.freedesktop.org/show_bug.cgi?id=105304
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: Michel Thierry <michel.thierry@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com> #v2
Link: https://patchwork.freedesktop.org/patch/msgid/20180428111532.15819-1-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
Add a selftest to ensure that we restore the whitelisted registers after
rewrite the registers everytime they might be scrubbed, e.g. module
load, reset and resume. For the other volatile workaround registers, we
export their presence via debugfs and check in igt/gem_workarounds.
However, we don't export the whitelist and rather than do so, let's test
them directly in the kernel.
The test we use is to read the registers back from the CS (this helps us
be sure that the registers will be valid for MI_LRI etc). In order to
generate the expected list, we split intel_whitelist_workarounds_emit
into two phases, the first to build the list and the second to apply.
Inside the test, we only build the list and then check that list against
the hw.
v2: Filter out pre-gen8 as they do not have RING_NONPRIV.
v3: Drop unused engine parameter, no plans to use it now or future.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Oscar Mateo <oscar.mateo@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180414122754.569-1-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
This has grown to be a sizable amount of code, so move it to
its own file before we try to refactor anything. For the moment,
we are leaving behind the WA BB code and the WAs that get applied
(incorrectly) in init_clock_gating, but we will deal with it later.
v2: Use intel_ prefix for code that deals with the hardware (Chris)
v3: Rebased
v4:
- Rebased
- New license header
v5:
- Rebased
- Added some organisational notes to the file (Chris)
v6: Include DOC section in the documentation build (Jani)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[ickle: appease checkpatch, mostly]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/1523376767-18480-1-git-send-email-oscar.mateo@intel.com
We can refine our current execlists->queue_priority if we inspect
ELSP[1] rather than the head of the unsubmitted queue. Currently, we use
the unsubmitted queue and say that if a subsequent request is more
important than the current queue, we will rerun the submission tasklet
to evaluate the need for preemption. However, we only want to preempt if
we need to jump ahead of a currently executing request in ELSP. The
second reason for running the submission tasklet is amalgamate requests
into the active context on ELSP[0] to avoid a stall when ELSP[0] drains.
(Though repeatedly amalgamating requests into the active context and
triggering many lite-restore is off question gain, the goal really is to
put a context into ELSP[1] to cover the interrupt.) So if instead of
looking at the head of the queue, we look at the context in ELSP[1] we
can answer both of the questions more accurately -- we don't need to
rerun the submission tasklet unless our new request is important enough
to feed into, at least, ELSP[1].
v2: Add some comments from the discussion with Tvrtko.
v3: More commentary to cross-reference queue_request()
References: f6322eddaf ("drm/i915/preemption: Allow preemption between submission ports")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180411103929.27374-1-chris@chris-wilson.co.uk
Tvrtko uncovered a fun issue with recovering from a wedge device. In his
tests, he wedged the driver by injecting an unrecoverable hang whilst a
batch was spinning. As we reset the gpu in the middle of the spinner,
when resumed it would continue on from the next instruction in the ring
and write it's breadcrumb. However, on wedging we updated our
bookkeeping to indicate that the GPU had completed executing and would
restart from after the breadcrumb; so the emission of the stale
breadcrumb from before the reset came as a bit of a surprise.
A simple fix is to when rebinding the context into the GPU, we update
the ring register state in the context image to match our bookkeeping.
We already have to update the RING_START and RING_TAIL, so updating
RING_HEAD as well is trivial. This works because whenever we unbind the
context, we keep the bookkeeping in check; and on wedging we unbind all
contexts.
Testcase: igt/gem_eio
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/20180327210136.16750-1-chris@chris-wilson.co.uk
Tested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
When cancelling the requests and clearing out the ports following a
successful preemption completion, also clear the active flag. I had
assumed that all preemptions would be followed by an immediate dequeue
(preserving the active user flag), but under rare circumstances we may
be triggering a preemption for the second port only for it to have
completed before the preemotion kicks in; leaving execlists->active set
even though the system is now idle.
We can clear the flag inside the common execlists_cancel_port_requests()
as the other users also expect the semantics of active being cleared.
Fixes: f6322eddaf ("drm/i915/preemption: Allow preemption between submission ports")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
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/20180324125829.27026-1-chris@chris-wilson.co.uk
After resetting the GPU (or subset of engines), call synchronize_irq()
to flush any pending irq before proceeding with the cleanup. For a
device level reset, we disable the interupts around the reset, but when
resetting just one engine, we have to avoid such global disabling. This
leaves us open to an interrupt arriving for the engine as we try to
reset it. We already do try to flush the IIR following the reset, but we
have to ensure that the in-flight interrupt does not land after we start
cleaning up after the reset; enter synchronize_irq().
As it current stands, we very rarely, but fatally, see sequences such as:
2.... 57964564us : execlists_reset_prepare: rcs0
2.... 57964613us : execlists_reset: rcs0 seqno=424
0d.h1 57964615us : gen8_cs_irq_handler: rcs0 CS active=1
2d..1 57964617us : __i915_request_unsubmit: rcs0 fence 29:1056 <- global_seqno 1060
2.... 57964703us : execlists_reset_finish: rcs0
0..s. 57964705us : execlists_submission_tasklet: rcs0 awake?=1, active=0, irq-posted?=1
v2: Move the sync into the execlists reset handler so that we coordinate
the flush with disabling the interrupt handling and canceling the
pending interrupt.
v3: Just use synchronize_hardirq() to avoid the might_sleep(), we do not
yet have threaded-irq to worry about.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180322073533.5313-4-chris@chris-wilson.co.uk
Reviewed-by: Jeff McGee <jeff.mcgee@intel.com>
The only usage outside the intel_lrc.c file is in the ringbuffer
init, but the irq mask calculated there is then overwritten for
all engines that have a non-zero shift, so we can drop it.
This change is not aimed at code saving but at removing from
intel_engines information that does not apply to all gens that have
the engine. When checking without the temporary WARN_ON, code size
is basically unchanged.
v2: make the irq_shifts array static const
v3: rebase, move irq_shifts array to logical_ring_default_irqs
v4: move array inside the if and use u8 for it (Chris)
Suggested-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
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/20180314182653.26981-4-daniele.ceraolospurio@intel.com
Up to now, subslice mask was assumed to be uniform across slices. But
starting with Cannonlake, slices can be asymmetric (for example slice0
has different number of subslices as slice1+). This change stores all
subslices masks for all slices rather than having a single mask that
applies to all slices.
v2: Rework how we store total numbers in sseu_dev_info (Tvrtko)
Fix CHV eu masks, was reading disabled as enabled (Tvrtko)
Readability changes (Tvrtko)
Add EU index helper (Tvrtko)
v3: Turn ALIGN(v, 8) / 8 into DIV_ROUND_UP(v, BITS_PER_BYTE) (Tvrtko)
Reuse sseu_eu_idx() for setting eu_mask on CHV (Tvrtko)
Reformat debug prints for subslices (Tvrtko)
v4: Change eu_mask helper into sseu_set_eus() (Tvrtko)
v5: With Haswell reporting masks & counts, bump sseu_*_eus() functions
to use u16 (Lionel)
v6: Fix sseu_get_eus() for > 8 EUs per subslice (Lionel)
v7: Change debugfs enabels for number of subslices per slice, will
need a small igt/pm_sseu change (Lionel)
Drop subslice_total field from sseu_dev_info, rely on
sseu_subslice_total() to recompute the value instead (Lionel)
v8: Remove unused function compute_subslice_total() (Lionel)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180306122857.27317-2-lionel.g.landwerlin@intel.com
Enhanced Execlists is an upgraded version of execlists which supports
up to 8 ports. The lrcs to be submitted are written to a submit queue
(the ExecLists Submission Queue - ELSQ), which is then loaded on the
HW. When writing to the ELSP register, the lrcs are written cyclically
in the queue from position 0 to position 7. Alternatively, it is
possible to write directly in the individual positions of the queue
using the ELSQC registers. To be able to re-use all the existing code
we're using the latter method and we're currently limiting ourself to
only using 2 elements.
v2: Rebase.
v3: Switch from !IS_GEN11 to GEN < 11 (Daniele Ceraolo Spurio).
v4: Use the elsq registers instead of elsp. (Daniele Ceraolo Spurio)
v5: Reword commit, rename regs to be closer to specs, turn off
preemption (Daniele), reuse engine->execlists.elsp (Chris)
v6: use has_logical_ring_elsq to differentiate the new paths
v7: add preemption support, rename els to submit_reg (Chris)
v8: save the ctrl register inside the execlists struct, drop CSB
handling updates (superseded by preempt_complete_status) (Chris)
v9: s/drm_i915_gem_request/i915_request (Mika)
v10: resolved conflict in inject_preempt_context (Mika)
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Thomas Daniel <thomas.daniel@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
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/20180302161501.28594-4-mika.kuoppala@linux.intel.com
Starting from Gen11 the context descriptor format has been updated in
the HW. The hw_id field has been considerably reduced in size and engine
class and instance fields have been added.
There is a slight name clashing issue because the field that we call
hw_id is actually called SW Context ID in the specs for Gen11+.
With the current size of the hw_id field we can have a maximum of 2k
contexts at any time, but we could use the sw_counter field (which is sw
defined) to increase that because the HW requirement is that
engine_id + sw id + sw_counter is a unique number.
GuC uses a similar method to support more contexts but does its tracking
at lrc level. To avoid doing an implementation that will need to be
reworked once GuC support lands, defer it for now and mark it as TODO.
v2: rebased, add documentation, fix GEN11_ENGINE_INSTANCE_SHIFT
v3: rebased, bring back lost code from i915_gem_context.c
v4: make TODO comment more generic
v5: be consistent with bit ordering, add extra checks (Chris)
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Oscar Mateo <oscar.mateo@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180302161501.28594-3-mika.kuoppala@linux.intel.com
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Sometimes we need to boost the priority of an in-flight request, which
may lead to the situation where the second submission port then contains
a higher priority context than the first and so we need to inject a
preemption event. To do so we must always check inside
execlists_dequeue() whether there is a priority inversion between the
ports themselves as well as the head of the priority sorted queue, and we
cannot just skip dequeuing if the queue is empty.
As Michał noted, this doesn't simply extend to handling more than 2-port
submission, as we may need to reorder within the array of executing
requests which themselves are lower priority than the first. A task for
later!
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180222142229.14517-1-chris@chris-wilson.co.uk
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
This workaround should prevent a bug that can be hit on a context
restore. To avoid the issue, we must emit a PIPE_CONTROL with CS stall
(0x7a000004 0x00100000 0x00000000 0x00000000) followed by 12DW's of
NOOP(0x0) in the indirect context batch buffer, to ensure the engine is
idle prior to programming 3DSTATE_SAMPLE_PATTERN.
It's also not clear whether we should add those extra dwords because of
the workaround itself, or if that's just padding for the WA BB (and next
commands could come right after the PIPE_CONTROL). We keep them for now.
References: HSD#1939868
v2: More descriptive changelog and comments.
v3: Explain that PIPE_CONTROL is actually 6 dwords, and that we advance
10 more dwords because of that.
Signed-off-by: Rafael Antognolli <rafael.antognolli@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Acked-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/20180205233330.14973-1-rafael.antognolli@intel.com
This patch clears a single bit. The bit is 0 by default but expected
not to be set. Explicitly clearing the bit in this patch is intended
to indicate some thinking has occurred, and that we want this bit
cleared and we are not just excepting the default value.
We also stop setting GFX_RUN_LIST_ENABLE, which is correct since that
bit is gone.
v2 (from Paulo): fix indentation.
v3: Changed GEN check to >= 11. Corrected author name.
v4 (from Paulo): improve commit message (Daniele).
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Kelvin Gardiner <kelvin.gardiner@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180130134918.32283-9-paulo.r.zanoni@intel.com
