drm/i915: Stop second guessing the caller for intel_uncore_wait_for_register() (84d84cb7) · Commits · 戴 / test

Allow the caller to use the fast_timeout_us to specify how long to wait within the atomic section, rather than transparently switching to a sleeping loop for larger values. This is required as some callsites may need a long wait and are in an atomic section. v2: Reinforce kerneldoc fast_timeout_us limit with a GEM_BUG_ON Signed-off-by:

Chris Wilson <chris@chris-wilson.co.uk> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170411112705.12656-1-chris@chris-wilson.co.uk Reviewed-by:

Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drivers/gpu/drm/i915/intel_uncore.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -1601,7 +1601,7 @@ static int gen6_reset_engines(struct drm_i915_private *dev_priv,
		*
		* Otherwise, the wait will timeout after @slow_timeout_ms milliseconds.
		* For atomic context @slow_timeout_ms must be zero and @fast_timeout_us
		* must be not larger than 10 microseconds.
		* must be not larger than 20,0000 microseconds.
		*
		* Note that this routine assumes the caller holds forcewake asserted, it is
		* not suitable for very long waits. See intel_wait_for_register() if you
		@@ -1623,16 +1623,18 @@ int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv,
		int ret;

		/* Catch any overuse of this function */
		might_sleep_if(fast_timeout_us > 10 \|\| slow_timeout_ms);
		might_sleep_if(slow_timeout_ms);
		GEM_BUG_ON(fast_timeout_us > 20000);

		if (fast_timeout_us > 10)
		ret = _wait_for(done, fast_timeout_us, 10);
		else
		ret = -ETIMEDOUT;
		if (fast_timeout_us && fast_timeout_us <= 20000)
		ret = _wait_for_atomic(done, fast_timeout_us, 0);
		if (ret)
		ret = wait_for(done, slow_timeout_ms);

		if (out_value)
		*out_value = reg_value;

		return ret;
		#undef done
		}

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