diff --git a/hardware/serial-dmm/api.c b/hardware/serial-dmm/api.c
index 6e9eaa24..d29af1b5 100644
--- a/hardware/serial-dmm/api.c
+++ b/hardware/serial-dmm/api.c
@@ -255,6 +255,7 @@ static GSList *scan(const char *conn, const char *serialcomm, int dmm)
 	}
 
 	devc->serial = serial;
+	devc->subdriver = dmm;
 
 	sdi->priv = devc;
 	sdi->driver = dmms[dmm].di;
@@ -446,7 +447,7 @@ static int hw_dev_acquisition_start(const struct sr_dev_inst *sdi,
 
 	/* Poll every 50ms, or whenever some data comes in. */
 	sr_source_add(devc->serial->fd, G_IO_IN, 50,
-		      dmms[sdi->driver->subdriver].receive_data, (void *)sdi);
+		      dmms[devc->subdriver].receive_data, (void *)sdi);
 
 	return SR_OK;
 }
@@ -512,7 +513,6 @@ SR_PRIV struct sr_dev_driver ID##_driver_info = { \
 	.dev_acquisition_start = hw_dev_acquisition_start, \
 	.dev_acquisition_stop = hw_dev_acquisition_stop, \
 	.priv = NULL, \
-	.subdriver = ID_UPPER, \
 };
 
 DRV(digitek_dt4000zc, DIGITEK_DT4000ZC, "digitek-dt4000zc", "Digitek DT4000ZC")
diff --git a/hardware/serial-dmm/protocol.h b/hardware/serial-dmm/protocol.h
index 77f89c74..7540d806 100644
--- a/hardware/serial-dmm/protocol.h
+++ b/hardware/serial-dmm/protocol.h
@@ -81,6 +81,7 @@ struct dev_context {
 	uint8_t buf[DMM_BUFSIZE];
 	int bufoffset;
 	int buflen;
+	int subdriver;
 };
 
 SR_PRIV int receive_data_DIGITEK_DT4000ZC(int fd, int revents, void *cb_data);
diff --git a/libsigrok.h b/libsigrok.h
index 90a57f79..d68ec143 100644
--- a/libsigrok.h
+++ b/libsigrok.h
@@ -631,8 +631,6 @@ struct sr_dev_driver {
 
 	/* Dynamic */
 	void *priv;
-
-	int subdriver;
 };
 
 struct sr_session {