From 48921260b7d030ec6a2e11a435eae28ddb88ea56 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 11 Apr 2017 18:58:50 +0100 Subject: [PATCH] drm/i915/execlists: Document runtime pm for intel_lrc_irq_handler() We indirectly hold the runtime-pm for the intel_lrc_irq_handler() by virtue of dev_priv->gt.awake keeping a wakeref whilst the requests are busy. As this is not obvious from the code, add a comment. Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Link: http://patchwork.freedesktop.org/patch/msgid/20170411175850.2470-1-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/intel_lrc.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 711125a7624c..7df278fe492e 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -515,6 +515,15 @@ static void intel_lrc_irq_handler(unsigned long data) struct execlist_port *port = engine->execlist_port; struct drm_i915_private *dev_priv = engine->i915; + /* We can skip acquiring intel_runtime_pm_get() here as it was taken + * on our behalf by the request (see i915_gem_mark_busy()) and it will + * not be relinquished until the device is idle (see + * i915_gem_idle_work_handler()). As a precaution, we make sure + * that all ELSP are drained i.e. we have processed the CSB, + * before allowing ourselves to idle and calling intel_runtime_pm_put(). + */ + GEM_BUG_ON(!dev_priv->gt.awake); + intel_uncore_forcewake_get(dev_priv, engine->fw_domains); /* Prefer doing test_and_clear_bit() as a two stage operation to avoid