hack the request length for the first get device descriptor if EP0 size =8 or 16

to prevent usbd control send out ZLP

1 files changed, 4 insertions, 0 deletions

diff --git a/src/device/usbd.c b/src/device/usbd.c
index 8661717f5..360881f34 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -771,9 +771,13 @@ static bool process_get_descriptor(uint8_t rhport, tusb_control_request_t const
       uint16_t len = sizeof(tusb_desc_device_t);

 

       // Only send up to EP0 Packet Size if not addressed

+      // This only happens with the very first get device descriptor and EP0 size = 8 or 16.

       if ((CFG_TUD_ENDPOINT0_SIZE < sizeof(tusb_desc_device_t)) && !_usbd_dev.addressed)

       {

         len = CFG_TUD_ENDPOINT0_SIZE;

+

+        // Hack here: we modify the request length to prevent usbd_control response with zlp

+        ((tusb_control_request_t*) p_request)->wLength = CFG_TUD_ENDPOINT0_SIZE;

       }

 

       return tud_control_xfer(rhport, p_request, (void*) tud_descriptor_device_cb(), len);