Rework audio driver

1 files changed, 5 insertions, 3 deletions

diff --git a/src/portable/st/synopsys/dcd_synopsys.c b/src/portable/st/synopsys/dcd_synopsys.c
index 90fcd51e7..4cb6028cc 100644
--- a/src/portable/st/synopsys/dcd_synopsys.c
+++ b/src/portable/st/synopsys/dcd_synopsys.c
@@ -670,13 +670,15 @@ bool dcd_edpt_xfer (uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t
   return true;
 }
 
-bool dcd_edpt_iso_xfer (uint8_t rhport, uint8_t ep_addr, tu_fifo_t * ff)
+// The number of bytes has to be given explicitly to allow more flexible control of how many
+// bytes should be written and second to keep the return value free to give back a boolean
+// success message. If total_bytes is too big, the FIFO will copy only what is available
+// into the USB buffer!
+bool dcd_edpt_iso_xfer (uint8_t rhport, uint8_t ep_addr, tu_fifo_t * ff, uint16_t total_bytes)
 {
   // USB buffers always work in bytes so to avoid unnecessary divisions we demand item_size = 1
   TU_ASSERT(ff->item_size == 1);
 
-  uint16_t total_bytes = tu_fifo_count(ff);
-
   uint8_t const epnum = tu_edpt_number(ep_addr);
   uint8_t const dir   = tu_edpt_dir(ep_addr);