diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c
index 6859af0..7611def 100644
--- a/drivers/staging/comedi/drivers/ni_labpc.c
+++ b/drivers/staging/comedi/drivers/ni_labpc.c
@@ -241,8 +241,10 @@ static int labpc_eeprom_write_insn(struct comedi_device *dev,
 				   struct comedi_insn *insn,
 				   unsigned int *data);
 static void labpc_adc_timing(struct comedi_device *dev, struct comedi_cmd *cmd);
-#ifdef CONFIG_COMEDI_PCI
+#ifdef CONFIG_ISA_DMA_API
 static unsigned int labpc_suggest_transfer_size(struct comedi_cmd cmd);
+#endif
+#ifdef CONFIG_COMEDI_PCI
 static int labpc_find_device(struct comedi_device *dev, int bus, int slot);
 #endif
 static int labpc_dio_mem_callback(int dir, int port, int data,