diff --git a/src/hardware/chronovu-la/api.c b/src/hardware/chronovu-la/api.c
index b6c3af47..0508250c 100644
--- a/src/hardware/chronovu-la/api.c
+++ b/src/hardware/chronovu-la/api.c
@@ -399,8 +399,9 @@ static int config_list(uint32_t key, GVariant **data, const struct sr_dev_inst *
 					devopts, ARRAY_SIZE(devopts), sizeof(uint32_t));
 		break;
 	case SR_CONF_SAMPLERATE:
-		if (!sdi || !sdi->priv || !(devc = sdi->priv))
+		if (!sdi)
 			return SR_ERR_BUG;
+		devc = sdi->priv;
 		cv_fill_samplerates_if_needed(sdi);
 		g_variant_builder_init(&gvb, G_VARIANT_TYPE("a{sv}"));
 		gvar = g_variant_new_fixed_array(G_VARIANT_TYPE("t"),
diff --git a/src/hardware/fx2lafw/api.c b/src/hardware/fx2lafw/api.c
index 08fbbcd8..54db1f36 100644
--- a/src/hardware/fx2lafw/api.c
+++ b/src/hardware/fx2lafw/api.c
@@ -740,8 +740,6 @@ static int config_list(uint32_t key, GVariant **data,
 		*data = g_variant_builder_end(&gvb);
 		break;
 	case SR_CONF_SAMPLERATE:
-		if (!sdi->priv)
-			return SR_ERR_ARG;
 		devc = sdi->priv;
 		g_variant_builder_init(&gvb, G_VARIANT_TYPE("a{sv}"));
 		gvar = g_variant_new_fixed_array(G_VARIANT_TYPE("t"), devc->samplerates,
diff --git a/src/hardware/hameg-hmo/api.c b/src/hardware/hameg-hmo/api.c
index 4b50b7aa..29dbe917 100644
--- a/src/hardware/hameg-hmo/api.c
+++ b/src/hardware/hameg-hmo/api.c
@@ -487,7 +487,8 @@ static int config_list(uint32_t key, GVariant **data, const struct sr_dev_inst *
 	struct dev_context *devc = NULL;
 	const struct scope_config *model = NULL;
 
-	if (sdi && (devc = sdi->priv)) {
+	if (sdi) {
+		devc = sdi->priv;
 		if ((cg_type = check_channel_group(devc, cg)) == CG_INVALID)
 			return SR_ERR;
 
diff --git a/src/hardware/korad-kaxxxxp/api.c b/src/hardware/korad-kaxxxxp/api.c
index 19daff8b..e008cfe4 100644
--- a/src/hardware/korad-kaxxxxp/api.c
+++ b/src/hardware/korad-kaxxxxp/api.c
@@ -288,7 +288,6 @@ static int config_set(uint32_t key, GVariant *data,
 static int config_list(uint32_t key, GVariant **data,
 	const struct sr_dev_inst *sdi, const struct sr_channel_group *cg)
 {
-
 	struct dev_context *devc;
 	GVariant *gvar;
 	GVariantBuilder gvb;
diff --git a/src/hardware/motech-lps-30x/api.c b/src/hardware/motech-lps-30x/api.c
index 57bc1d26..57befbfd 100644
--- a/src/hardware/motech-lps-30x/api.c
+++ b/src/hardware/motech-lps-30x/api.c
@@ -700,7 +700,7 @@ static int config_list(uint32_t key, GVariant **data, const struct sr_dev_inst *
 			scanopts, ARRAY_SIZE(scanopts), sizeof(uint32_t));
 		return SR_OK;
 	case SR_CONF_DEVICE_OPTIONS:
-		if (sdi != NULL)
+		if (sdi)
 			break;
 		*data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
 			drvopts, ARRAY_SIZE(drvopts), sizeof(uint32_t));
diff --git a/src/hardware/rigol-ds/api.c b/src/hardware/rigol-ds/api.c
index a88d1ba2..e7436083 100644
--- a/src/hardware/rigol-ds/api.c
+++ b/src/hardware/rigol-ds/api.c
@@ -805,8 +805,9 @@ static int config_list(uint32_t key, GVariant **data, const struct sr_dev_inst *
 	}
 
 	/* Every other option requires a valid device instance. */
-	if (!sdi || !(devc = sdi->priv))
+	if (!sdi)
 		return SR_ERR_ARG;
+	devc = sdi->priv;
 
 	/* If a channel group is specified, it must be a valid one. */
 	if (cg && !g_slist_find(sdi->channel_groups, cg)) {
diff --git a/src/hwdriver.c b/src/hwdriver.c
index fafd93fc..6758f6a9 100644
--- a/src/hwdriver.c
+++ b/src/hwdriver.c
@@ -710,8 +710,10 @@ SR_API int sr_config_get(const struct sr_dev_driver *driver,
 	if (check_key(driver, sdi, cg, key, SR_CONF_GET, NULL) != SR_OK)
 		return SR_ERR_ARG;
 
-	if (sdi && !sdi->priv)
+	if (sdi && !sdi->priv) {
+		sr_err("Can't get config (sdi != NULL, sdi->priv == NULL).");
 		return SR_ERR;
+	}
 
 	if ((ret = driver->config_get(key, data, sdi, cg)) == SR_OK) {
 		log_key(sdi, cg, key, SR_CONF_GET, *data);
@@ -793,9 +795,11 @@ SR_API int sr_config_commit(const struct sr_dev_inst *sdi)
 /**
  * List all possible values for a configuration key.
  *
- * @param[in] driver The sr_dev_driver struct to query.
+ * @param[in] driver The sr_dev_driver struct to query. Must not be NULL.
  * @param[in] sdi (optional) If the key is specific to a device, this must
  *            contain a pointer to the struct sr_dev_inst to be checked.
+ *            Otherwise it must be NULL. If sdi is != NULL, sdi->priv must
+ *            also be != NULL.
  * @param[in] cg The channel group on the device for which to list the
  *                    values, or NULL.
  * @param[in] key The configuration key (SR_CONF_*).
@@ -828,6 +832,10 @@ SR_API int sr_config_list(const struct sr_dev_driver *driver,
 		if (check_key(driver, sdi, cg, key, SR_CONF_LIST, NULL) != SR_OK)
 			return SR_ERR_ARG;
 	}
+	if (sdi && !sdi->priv) {
+		sr_err("Can't list config (sdi != NULL, sdi->priv == NULL).");
+		return SR_ERR;
+	}
 	if ((ret = driver->config_list(key, data, sdi, cg)) == SR_OK) {
 		log_key(sdi, cg, key, SR_CONF_LIST, *data);
 		g_variant_ref_sink(*data);
diff --git a/src/lcr/es51919.c b/src/lcr/es51919.c
index f1e27acb..3b32df1e 100644
--- a/src/lcr/es51919.c
+++ b/src/lcr/es51919.c
@@ -894,7 +894,6 @@ SR_PRIV int es51919_serial_config_list(uint32_t key, GVariant **data,
 		*data = g_variant_new_strv(models, ARRAY_SIZE(models));
 		break;
 	default:
-		sr_spew("%s: Unsupported key %u", __func__, key);
 		return SR_ERR_NA;
 	}