From d26e55085f4b7a63677670db827541209257b313 Mon Sep 17 00:00:00 2001 From: Vinay Belgaumkar Date: Mon, 28 Apr 2025 11:35:55 -0700 Subject: [PATCH] drm/i915/slpc: Balance the inc/dec for num_waiters As seen in some recent failures, SLPC num_waiters value is < 0. This happens because the inc/dec are not balanced. We should skip decrement for the same conditions as the increment. Currently, we do that for power saving profile mode. This patch also ensures that num_waiters is incremented in the case min_softlimit is at boost freq. It ensures that we don't reduce the frequency while this request is in flight. v2: Add Fixes tags Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13598 Fixes: f864a29afc32 ("drm/i915/slpc: Optmize waitboost for SLPC") Fixes: 4a82ceb04ad4 ("drm/i915/slpc: Add sysfs for SLPC power profiles") Cc: Sk Anirban Reviewed-by: Sk Anirban Signed-off-by: Vinay Belgaumkar Signed-off-by: Daniele Ceraolo Spurio Link: https://lore.kernel.org/r/20250428183555.3250021-1-vinay.belgaumkar@intel.com --- drivers/gpu/drm/i915/gt/intel_rps.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c index 2cfaedb04876..373aa2a266fd 100644 --- a/drivers/gpu/drm/i915/gt/intel_rps.c +++ b/drivers/gpu/drm/i915/gt/intel_rps.c @@ -1001,6 +1001,10 @@ void intel_rps_dec_waiters(struct intel_rps *rps) if (rps_uses_slpc(rps)) { slpc = rps_to_slpc(rps); + /* Don't decrement num_waiters for req where increment was skipped */ + if (slpc->power_profile == SLPC_POWER_PROFILES_POWER_SAVING) + return; + intel_guc_slpc_dec_waiters(slpc); } else { atomic_dec(&rps->num_waiters); @@ -1029,11 +1033,15 @@ void intel_rps_boost(struct i915_request *rq) if (slpc->power_profile == SLPC_POWER_PROFILES_POWER_SAVING) return; - if (slpc->min_freq_softlimit >= slpc->boost_freq) - return; - /* Return if old value is non zero */ if (!atomic_fetch_inc(&slpc->num_waiters)) { + /* + * Skip queuing boost work if frequency is already boosted, + * but still increment num_waiters. + */ + if (slpc->min_freq_softlimit >= slpc->boost_freq) + return; + GT_TRACE(rps_to_gt(rps), "boost fence:%llx:%llx\n", rq->fence.context, rq->fence.seqno); queue_work(rps_to_gt(rps)->i915->unordered_wq, -- 2.25.1