[Intel-gfx] [PATCH] drm/i915: Park faster to alleviate kept forcewake

[Mika Kuoppala]

To avoid context corruption on some gens, we need to hold forcewake
for long periods of time. This leads to increased energy expenditure
for mostly idle workloads.

To combat the increased power consumption, park GPU more hastily.

As the HW isn't so quick to end up in rc6, this software mechanism
supplements it. So we can apply it, across all gens.

Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
Testcase: igt/i915_pm_rc6_residency/rc6-idle
References: "Add RC6 CTX corruption WA"
Cc: Stable <stable at vger.kernel.org>    # v4.19+
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c  | 2 +-
 drivers/gpu/drm/i915/intel_lrc.c | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c7d05ac7af3c..6ddc75098b28 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -197,7 +197,7 @@ void i915_gem_park(struct drm_i915_private *i915)
 		return;
 
 	/* Defer the actual call to __i915_gem_park() to prevent ping-pongs */
-	mod_delayed_work(i915->wq, &i915->gt.idle_work, msecs_to_jiffies(100));
+	mod_delayed_work(i915->wq, &i915->gt.idle_work, 1);
 }
 
 void i915_gem_unpark(struct drm_i915_private *i915)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 13e97faabaa7..284ffdfd8840 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -388,7 +388,12 @@ execlists_user_begin(struct intel_engine_execlists *execlists,
 inline void
 execlists_user_end(struct intel_engine_execlists *execlists)
 {
+	struct intel_engine_cs *engine =
+		container_of(execlists, typeof(*engine), execlists);
+
 	execlists_clear_active(execlists, EXECLISTS_ACTIVE_USER);
+
+	mod_delayed_work(engine->i915->wq, &engine->i915->gt.retire_work, 0);
 }
 
 static inline void
-- 
2.17.1