From d9ffaa62cc4584013a40f75cf6e5681d002fe4fb Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Sun, 22 Mar 2020 16:32:24 +0000
Subject: drm/i915/gt: Treat idling as a RPS downclock event
Git-commit: 98479ada421a8fd2123b98efd398a6f1379307ab
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
If we park/unpark faster than we can respond to RPS events, we never
will process a downclock event after expiring a waitboost, and thus we
will forever restart the GPU at max clocks even if the workload switches
and doesn't justify full power.
Closes: https://gitlab.freedesktop.org/drm/intel/issues/1500
Fixes: 3e7abf814193 ("drm/i915: Extract GT render power state management")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: Lyude Paul <lyude@redhat.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200322163225.28791-1-chris@chris-wilson.co.uk
Cc: <stable@vger.kernel.org> # v5.5+
(cherry picked from commit 21abf0bf168dffff1192e0f072af1dc74ae1ff0e)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gt/intel_rps.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
index 87f9638d2cbf..cfaf141bac4d 100644
--- a/drivers/gpu/drm/i915/gt/intel_rps.c
+++ b/drivers/gpu/drm/i915/gt/intel_rps.c
@@ -770,6 +770,19 @@ void intel_rps_park(struct intel_rps *rps)
intel_uncore_forcewake_get(rps_to_uncore(rps), FORCEWAKE_MEDIA);
rps_set(rps, rps->idle_freq, false);
intel_uncore_forcewake_put(rps_to_uncore(rps), FORCEWAKE_MEDIA);
+
+ /*
+ * Since we will try and restart from the previously requested
+ * frequency on unparking, treat this idle point as a downclock
+ * interrupt and reduce the frequency for resume. If we park/unpark
+ * more frequently than the rps worker can run, we will not respond
+ * to any EI and never see a change in frequency.
+ *
+ * (Note we accommodate Cherryview's limitation of only using an
+ * even bin by applying it to all.)
+ */
+ rps->cur_freq =
+ max_t(int, round_down(rps->cur_freq - 1, 2), rps->min_freq);
}
void intel_rps_boost(struct i915_request *rq)
--
2.28.0