On suspend, the rc6 residency counters (stored in HW registers) will be
lost and cleared. However, we keep track of the rc6 residency to provide
a continuous 64b sampling, and if we see the HW value go backwards, we
assume it overflowed and add on 32b/40b -- an interesting artifact when
sampling across suspend.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_rc6.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_rc6.c b/drivers/gpu/drm/i915/gt/intel_rc6.c
index 9e303c29d6e3..04eeb7740e53 100644
--- a/drivers/gpu/drm/i915/gt/intel_rc6.c
+++ b/drivers/gpu/drm/i915/gt/intel_rc6.c
@@ -542,6 +542,8 @@ void intel_rc6_init(struct intel_rc6 *rc6)
void intel_rc6_sanitize(struct intel_rc6 *rc6)
{
+ memset(rc6->prev_hw_residency, 0, sizeof(rc6->prev_hw_residency));
+
if (rc6->enabled) { /* unbalanced suspend/resume */
rpm_get(rc6);
rc6->enabled = false;
--
2.25.0.rc2
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