drm/i915/gt: Expose reset stop timeout via sysfs

	  that the reset itself may take longer and so be more disruptive to

	  interactive or low latency workloads.

	  This is adjustable via

	  /sys/class/drm/card?/engine/*/stop_timeout_ms

config DRM_I915_TIMESLICE_DURATION

	int "Scheduling quantum for userspace batches (ms, jiffy granularity)"

	default 1 # milliseconds

static struct kobj_attribute timeslice_duration_attr =

__ATTR(timeslice_duration_ms, 0644, timeslice_show, timeslice_store);

static ssize_t

stop_store(struct kobject *kobj, struct kobj_attribute *attr,

	   const char *buf, size_t count)

{

	struct intel_engine_cs *engine = kobj_to_engine(kobj);

	unsigned long long duration;

	int err;

	/*

	 * When we allow ourselves to sleep before a GPU reset after disabling

	 * submission, even for a few milliseconds, gives an innocent context

	 * the opportunity to clear the GPU before the reset occurs. However,

	 * how long to sleep depends on the typical non-preemptible duration

	 * (a similar problem to determining the ideal preempt-reset timeout

	 * or even the heartbeat interval).

	 */

	err = kstrtoull(buf, 0, &duration);

	if (err)

		return err;

	if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))

		return -EINVAL;

	WRITE_ONCE(engine->props.stop_timeout_ms, duration);

	return count;

}

static ssize_t

stop_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)

{

	struct intel_engine_cs *engine = kobj_to_engine(kobj);

	return sprintf(buf, "%lu\n", engine->props.stop_timeout_ms);

}

static struct kobj_attribute stop_timeout_attr =

__ATTR(stop_timeout_ms, 0644, stop_show, stop_store);

static void kobj_engine_release(struct kobject *kobj)

{

	kfree(kobj);

		&caps_attr.attr,

		&all_caps_attr.attr,

		&max_spin_attr.attr,

		&stop_timeout_attr.attr,

		NULL

	};