diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 4e6ad74..b0be092 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -265,12 +265,12 @@ struct snd_ratden {
 
 struct snd_pcm_hw_constraint_ratnums {
 	int nrats;
-	struct snd_ratnum *rats;
+	const struct snd_ratnum *rats;
 };
 
 struct snd_pcm_hw_constraint_ratdens {
 	int nrats;
-	struct snd_ratden *rats;
+	const struct snd_ratden *rats;
 };
 
 struct snd_pcm_hw_constraint_list {
@@ -970,7 +970,7 @@ int snd_interval_list(struct snd_interval *i, unsigned int count,
 int snd_interval_ranges(struct snd_interval *i, unsigned int count,
 			const struct snd_interval *list, unsigned int mask);
 int snd_interval_ratnum(struct snd_interval *i,
-			unsigned int rats_count, struct snd_ratnum *rats,
+			unsigned int rats_count, const struct snd_ratnum *rats,
 			unsigned int *nump, unsigned int *denp);
 
 void _snd_pcm_hw_params_any(struct snd_pcm_hw_params *params);
@@ -1000,11 +1000,11 @@ int snd_pcm_hw_constraint_ranges(struct snd_pcm_runtime *runtime,
 int snd_pcm_hw_constraint_ratnums(struct snd_pcm_runtime *runtime, 
 				  unsigned int cond,
 				  snd_pcm_hw_param_t var,
-				  struct snd_pcm_hw_constraint_ratnums *r);
+				  const struct snd_pcm_hw_constraint_ratnums *r);
 int snd_pcm_hw_constraint_ratdens(struct snd_pcm_runtime *runtime, 
 				  unsigned int cond,
 				  snd_pcm_hw_param_t var,
-				  struct snd_pcm_hw_constraint_ratdens *r);
+				  const struct snd_pcm_hw_constraint_ratdens *r);
 int snd_pcm_hw_constraint_msbits(struct snd_pcm_runtime *runtime, 
 				 unsigned int cond,
 				 unsigned int width,
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 05a3ca9..6b5a811 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -801,7 +801,7 @@ void snd_interval_mulkdiv(const struct snd_interval *a, unsigned int k,
  * negative error code.
  */
 int snd_interval_ratnum(struct snd_interval *i,
-			unsigned int rats_count, struct snd_ratnum *rats,
+			unsigned int rats_count, const struct snd_ratnum *rats,
 			unsigned int *nump, unsigned int *denp)
 {
 	unsigned int best_num, best_den;
@@ -920,7 +920,8 @@ EXPORT_SYMBOL(snd_interval_ratnum);
  * negative error code.
  */
 static int snd_interval_ratden(struct snd_interval *i,
-			       unsigned int rats_count, struct snd_ratden *rats,
+			       unsigned int rats_count,
+			       const struct snd_ratden *rats,
 			       unsigned int *nump, unsigned int *denp)
 {
 	unsigned int best_num, best_diff, best_den;
@@ -1339,7 +1340,7 @@ EXPORT_SYMBOL(snd_pcm_hw_constraint_ranges);
 static int snd_pcm_hw_rule_ratnums(struct snd_pcm_hw_params *params,
 				   struct snd_pcm_hw_rule *rule)
 {
-	struct snd_pcm_hw_constraint_ratnums *r = rule->private;
+	const struct snd_pcm_hw_constraint_ratnums *r = rule->private;
 	unsigned int num = 0, den = 0;
 	int err;
 	err = snd_interval_ratnum(hw_param_interval(params, rule->var),
@@ -1363,10 +1364,10 @@ static int snd_pcm_hw_rule_ratnums(struct snd_pcm_hw_params *params,
 int snd_pcm_hw_constraint_ratnums(struct snd_pcm_runtime *runtime, 
 				  unsigned int cond,
 				  snd_pcm_hw_param_t var,
-				  struct snd_pcm_hw_constraint_ratnums *r)
+				  const struct snd_pcm_hw_constraint_ratnums *r)
 {
 	return snd_pcm_hw_rule_add(runtime, cond, var,
-				   snd_pcm_hw_rule_ratnums, r,
+				   snd_pcm_hw_rule_ratnums, (void *)r,
 				   var, -1);
 }
 
@@ -1375,7 +1376,7 @@ EXPORT_SYMBOL(snd_pcm_hw_constraint_ratnums);
 static int snd_pcm_hw_rule_ratdens(struct snd_pcm_hw_params *params,
 				   struct snd_pcm_hw_rule *rule)
 {
-	struct snd_pcm_hw_constraint_ratdens *r = rule->private;
+	const struct snd_pcm_hw_constraint_ratdens *r = rule->private;
 	unsigned int num = 0, den = 0;
 	int err = snd_interval_ratden(hw_param_interval(params, rule->var),
 				  r->nrats, r->rats, &num, &den);
@@ -1398,10 +1399,10 @@ static int snd_pcm_hw_rule_ratdens(struct snd_pcm_hw_params *params,
 int snd_pcm_hw_constraint_ratdens(struct snd_pcm_runtime *runtime, 
 				  unsigned int cond,
 				  snd_pcm_hw_param_t var,
-				  struct snd_pcm_hw_constraint_ratdens *r)
+				  const struct snd_pcm_hw_constraint_ratdens *r)
 {
 	return snd_pcm_hw_rule_add(runtime, cond, var,
-				   snd_pcm_hw_rule_ratdens, r,
+				   snd_pcm_hw_rule_ratdens, (void *)r,
 				   var, -1);
 }
 
