[PATCH 2/2] drm/xe/lnl: Enable GuC SLPC DCC task

[Rodrigo Vivi]

Enable DCC (Duty Cycle Control) in Lunar Lake.

DCC is the SLPC task that tries to keep
the GT from operating inefficiently when thermally constrained.

Although the recommendation is to enable it, LNL GuC is leaving
it disabled by default on LNL.

It would minimize the GT frequency oscilation on throttled
scenarios, what could potentially reduce latencies.

v2: Move set_policies call after wait for running state, so
    we ensure it is not overwritten. (Vinay)

Cc: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/xe/xe_guc_pc.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_guc_pc.c b/drivers/gpu/drm/xe/xe_guc_pc.c
index 9f9e0642c796..4233679036de 100644
--- a/drivers/gpu/drm/xe/xe_guc_pc.c
+++ b/drivers/gpu/drm/xe/xe_guc_pc.c
@@ -956,6 +956,16 @@ static int pc_init_freqs(struct xe_guc_pc *pc)
 	return ret;
 }
 
+static int slpc_set_policies(struct xe_guc_pc *pc)
+{
+	struct xe_device *xe = pc_to_xe(pc);
+
+	if (xe->info.platform == XE_LUNARLAKE)
+		return pc_action_set_param(pc, SLPC_PARAM_TASK_ENABLE_DCC, 1);
+
+	return 0;
+}
+
 /**
  * xe_guc_pc_start - Start GuC's Power Conservation component
  * @pc: Xe_GuC_PC instance
@@ -1000,6 +1010,10 @@ int xe_guc_pc_start(struct xe_guc_pc *pc)
 		goto out;
 	}
 
+	ret = slpc_set_policies(pc);
+	if (ret)
+		goto out;
+
 	ret = pc_init_freqs(pc);
 	if (ret)
 		goto out;
-- 
2.47.1