drm/i915: Don't allow overuse of __intel_wait_for_register_fw() (6976e74b) · Commits · 戴 / test

This function should not be called with long timeouts in atomic context. Annotate it as might_sleep if timeout is longer than 10us. v2: fix comment (Michal) Signed-off-by:

Michal Wajdeczko <michal.wajdeczko@intel.com> Suggested-by:

Chris Wilson <chris@chris-wilson.co.uk> Cc: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/20170410121747.209200-1-michal.wajdeczko@intel.com Reviewed-by:

Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by:

Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/intel_uncore.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -1600,6 +1600,8 @@ static int gen6_reset_engines(struct drm_i915_private *dev_priv,
		* (I915_READ_FW(reg) & mask) == value
		*
		* 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.
		*
		* 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
		@@ -1620,6 +1622,9 @@ int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv,
		#define done (((reg_value = I915_READ_FW(reg)) & mask) == value)
		int ret;

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

		if (fast_timeout_us > 10)
		ret = _wait_for(done, fast_timeout_us, 10);
		else

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