drm/xe/pmu: Initialize PMU event types based on first available GT

GT ID#0 (primary GT on tile 0) may not always be available if the
primary GT has been disabled via configfs. Instead use the first
available GT when determining which PMU events are supported. If there
are no GTs, then don't advertise any GT-related events.

Reviewed-by: Lucas De Marchi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Matt Roper <[e-mail]>

drivers/gpu/drm/xe/xe_pmu.c

···
 static void set_supported_events(struct xe_pmu *pmu)
 {
 	struct xe_device *xe = container_of(pmu, typeof(*xe), pmu);
-	struct xe_gt *gt = xe_device_get_gt(xe, 0);
+	struct xe_gt *gt;
+	int id;
+
+	/* If there are no GTs, don't support any GT-related events */
+	if (xe->info.gt_count == 0)
+		return;
 
 	if (!xe->info.skip_guc_pc) {
 		pmu->supported_events |= BIT_ULL(XE_PMU_EVENT_GT_C6_RESIDENCY);
 		pmu->supported_events |= BIT_ULL(XE_PMU_EVENT_GT_ACTUAL_FREQUENCY);
 		pmu->supported_events |= BIT_ULL(XE_PMU_EVENT_GT_REQUESTED_FREQUENCY);
 	}
+
+	/* Find the first available GT to query engine event capabilities */
+	for_each_gt(gt, xe, id)
+		break;
 
 	if (xe_guc_engine_activity_supported(&gt->uc.guc)) {
 		pmu->supported_events |= BIT_ULL(XE_PMU_EVENT_ENGINE_ACTIVE_TICKS);