Patch "i915/guc: Reset engine utilization buffer before registration" has been added to the 6.12-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    i915/guc: Reset engine utilization buffer before registration

to the 6.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i915-guc-reset-engine-utilization-buffer-before-regi.patch
and it can be found in the queue-6.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3eb9a8e90e084ada12cd521e4b4fe9fbdd2eb000
Author: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@xxxxxxxxx>
Date:   Wed Nov 27 09:40:04 2024 -0800

    i915/guc: Reset engine utilization buffer before registration
    
    [ Upstream commit abcc2ddae5f82aa6cfca162e3db643dd33f0a2e8 ]
    
    On GT reset, we store total busyness counts for all engines and
    re-register the utilization buffer with GuC. At that time we should
    reset the buffer, so that we don't get spurious busyness counts on
    subsequent queries.
    
    To repro this issue, run igt@perf_pmu@busy-hang followed by
    igt@perf_pmu@most-busy-idle-check-all for a couple iterations.
    
    Fixes: 77cdd054dd2c ("drm/i915/pmu: Connect engine busyness stats from GuC to pmu")
    Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@xxxxxxxxx>
    Reviewed-by: John Harrison <John.C.Harrison@xxxxxxxxx>
    Link: https://patchwork.freedesktop.org/patch/msgid/20241127174006.190128-2-umesh.nerlige.ramappa@xxxxxxxxx
    (cherry picked from commit abd318237fa6556c1e5225529af145ef15d5ff0d)
    Signed-off-by: Tvrtko Ursulin <tursulin@xxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index ed979847187f..4793759f4d4a 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -1243,6 +1243,21 @@ static void __get_engine_usage_record(struct intel_engine_cs *engine,
 	} while (++i < 6);
 }
 
+static void __set_engine_usage_record(struct intel_engine_cs *engine,
+				      u32 last_in, u32 id, u32 total)
+{
+	struct iosys_map rec_map = intel_guc_engine_usage_record_map(engine);
+
+#define record_write(map_, field_, val_) \
+	iosys_map_wr_field(map_, 0, struct guc_engine_usage_record, field_, val_)
+
+	record_write(&rec_map, last_switch_in_stamp, last_in);
+	record_write(&rec_map, current_context_index, id);
+	record_write(&rec_map, total_runtime, total);
+
+#undef record_write
+}
+
 static void guc_update_engine_gt_clks(struct intel_engine_cs *engine)
 {
 	struct intel_engine_guc_stats *stats = &engine->stats.guc;
@@ -1543,6 +1558,9 @@ static void guc_timestamp_ping(struct work_struct *wrk)
 
 static int guc_action_enable_usage_stats(struct intel_guc *guc)
 {
+	struct intel_gt *gt = guc_to_gt(guc);
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
 	u32 offset = intel_guc_engine_usage_offset(guc);
 	u32 action[] = {
 		INTEL_GUC_ACTION_SET_ENG_UTIL_BUFF,
@@ -1550,6 +1568,9 @@ static int guc_action_enable_usage_stats(struct intel_guc *guc)
 		0,
 	};
 
+	for_each_engine(engine, gt, id)
+		__set_engine_usage_record(engine, 0, 0xffffffff, 0);
+
 	return intel_guc_send(guc, action, ARRAY_SIZE(action));
 }