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drm/i915/breadcrumbs: Keep the fake irq armed across reset 

Instead of synchronously cancelling the timer and re-enabling it inside
the reset callbacks, keep the timer enabled and let it die on its next
wakeup if no longer required. This allows
intel_engine_reset_breadcrumbs() to be used from an atomic
(timer/softirq) context such as required for resetting an engine.

It also allows us to react better to the user poking around debugfs for
testing missed irqs.

v2: Tighten the order of del_timer_sync as the fake_irq timer
may trigger the hangcheck timer, and so we should cancel it first and
then cancel the hangcheck (Mika)

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>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180424142945.6787-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2018-04-24 15:29:45 +01:00
parent a399715913
commit 36a501a199
1 changed files with 20 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/gpu/drm/i915/intel_breadcrumbs.c
View File

@ -130,11 +130,12 @@ static void intel_breadcrumbs_hangcheck(struct timer_list *t)
static void intel_breadcrumbs_fake_irq(struct timer_list *t)
{
struct intel_engine_cs *engine = from_timer(engine, t,
breadcrumbs.fake_irq);
struct intel_engine_cs *engine =
from_timer(engine, t, breadcrumbs.fake_irq);
struct intel_breadcrumbs *b = &engine->breadcrumbs;
/* The timer persists in case we cannot enable interrupts,
/*
* The timer persists in case we cannot enable interrupts,
* or if we have previously seen seqno/interrupt incoherency
* ("missed interrupt" syndrome, better known as a "missed breadcrumb").
* Here the worker will wake up every jiffie in order to kick the
@ -148,6 +149,12 @@ static void intel_breadcrumbs_fake_irq(struct timer_list *t)
if (!b->irq_armed)
return;
/* If the user has disabled the fake-irq, restore the hangchecking */
if (!test_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings)) {
mod_timer(&b->hangcheck, wait_timeout());
return;
}
mod_timer(&b->fake_irq, jiffies + 1);
}
@ -831,8 +838,8 @@ static void cancel_fake_irq(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
del_timer_sync(&b->fake_irq); /* may queue b->hangcheck */
del_timer_sync(&b->hangcheck);
del_timer_sync(&b->fake_irq);
clear_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
}
@ -840,15 +847,22 @@ void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
cancel_fake_irq(engine);
spin_lock_irq(&b->irq_lock);
/*
* Leave the fake_irq timer enabled (if it is running), but clear the
* bit so that it turns itself off on its next wake up and goes back
* to the long hangcheck interval if still required.
*/
clear_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
if (b->irq_enabled)
irq_enable(engine);
else
irq_disable(engine);
/* We set the IRQ_BREADCRUMB bit when we enable the irq presuming the
/*
* We set the IRQ_BREADCRUMB bit when we enable the irq presuming the
* GPU is active and may have already executed the MI_USER_INTERRUPT
* before the CPU is ready to receive. However, the engine is currently
* idle (we haven't started it yet), there is no possibility for a
@ -857,9 +871,6 @@ void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine)
*/
clear_bit(ENGINE_IRQ_BREADCRUMB, &engine->irq_posted);
if (b->irq_armed)
enable_fake_irq(b);
spin_unlock_irq(&b->irq_lock);
}