drm/xe/guc: Remove explicit shutdown of SLPC

SLPC shutdown is called in reset and suspend paths. In the reset
path, it is possible that the H2G call gets lost as GuC is in the
process of being reset. There is no value in stopping SLPC when
it will happen anyways.

In the suspend path, we disable communication with GuC, so there
is no need to explicitly shutdown SLPC.

v2: Rebase

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240325235602.1155486-1-vinay.belgaumkar@intel.com

drivers/gpu/drm/xe/xe_guc_pc.c

@@ -145,25 +145,6 @@ static int pc_action_reset(struct xe_guc_pc *pc)
 	return ret;
 }
 
-static int pc_action_shutdown(struct xe_guc_pc *pc)
-{
-	struct  xe_guc_ct *ct = &pc_to_guc(pc)->ct;
-	int ret;
-	u32 action[] = {
-		GUC_ACTION_HOST2GUC_PC_SLPC_REQUEST,
-		SLPC_EVENT(SLPC_EVENT_SHUTDOWN, 2),
-		xe_bo_ggtt_addr(pc->bo),
-		0,
-	};
-
-	ret = xe_guc_ct_send(ct, action, ARRAY_SIZE(action), 0, 0);
-	if (ret)
-		drm_err(&pc_to_xe(pc)->drm, "GuC PC shutdown %pe",
-			ERR_PTR(ret));
-
-	return ret;
-}
-
 static int pc_action_query_task_state(struct xe_guc_pc *pc)
 {
 	struct xe_guc_ct *ct = &pc_to_guc(pc)->ct;
@@ -893,7 +874,6 @@ int xe_guc_pc_start(struct xe_guc_pc *pc)
 int xe_guc_pc_stop(struct xe_guc_pc *pc)
 {
 	struct xe_device *xe = pc_to_xe(pc);
-	int ret;
 
 	if (xe->info.skip_guc_pc) {
 		xe_gt_idle_disable_c6(pc_to_gt(pc));
@@ -904,15 +884,6 @@ int xe_guc_pc_stop(struct xe_guc_pc *pc)
 	pc->freq_ready = false;
 	mutex_unlock(&pc->freq_lock);
 
-	ret = pc_action_shutdown(pc);
-	if (ret)
-		return ret;
-
-	if (wait_for_pc_state(pc, SLPC_GLOBAL_STATE_NOT_RUNNING)) {
-		drm_err(&pc_to_xe(pc)->drm, "GuC PC Shutdown failed\n");
-		return -EIO;
-	}
-
 	return 0;
 }