use actual max val in histogram if approx bigger than it

fw/apm.c

@@ -323,8 +323,9 @@ static inline bool
 tfw_stats_adj_min(TfwPcntRanges *rng, unsigned int r_time)
 {
 	if (r_time < rng->min_val) {
+		bool ret = rng->min_val != UINT_MAX;
 		rng->min_val = r_time;
-		return rng->min_val != UINT_MAX;
+		return ret;
 	}
 	return false;
 }
@@ -768,6 +769,7 @@ tfw_apm_prnctl_calc(TfwApmRBuf *rbuf, TfwApmRBCtl *rbctl, TfwPrcntlStats *pstats
 	TfwApmRBEState st[TFW_APM_MAX_TMWSCALE];
 	TfwPcntRanges *pcntrng;
 	TfwApmRBEnt *rbent = rbuf->rbent;
+	unsigned int max_val = 0;
 
 	for (i = 0; i < rbuf->rbufsz; i++) {
 		pcntrng = &rbent[i].pcntrng;
@@ -780,6 +782,11 @@ tfw_apm_prnctl_calc(TfwApmRBuf *rbuf, TfwApmRBCtl *rbctl, TfwPrcntlStats *pstats
 		if (!pval[i])
 			pstats->val[p++] = 0;
 	}
+	for (i = 0; i < rbuf->rbufsz; i++) {
+		pcntrng = &rbent[i].pcntrng;
+		if (max_val < pcntrng->max_val)
+			max_val = pcntrng->max_val;
+	}
 	while (p < T_PSZ) {
 		int v_min = USHRT_MAX;
 		for (i = 0; i < rbuf->rbufsz; i++) {
@@ -794,6 +801,9 @@ tfw_apm_prnctl_calc(TfwApmRBuf *rbuf, TfwApmRBCtl *rbctl, TfwPrcntlStats *pstats
 			cnt += pcntrng->cnt[st[i].r][st[i].b];
 			tfw_apm_state_next(pcntrng, &st[i]);
 		}
+		if (v_min > max_val) {
+			v_min = max_val;
+		}
 		for ( ; p < T_PSZ && pval[p] <= cnt; ++p)
 			pstats->val[p] = v_min;
 	}