kingst-la2016: setup usb transfer sizes to be multiple of endpoint max packet size...

[libsigrok.git] / src / hardware / kingst-la2016 / protocol.c

diff --git a/src/hardware/kingst-la2016/protocol.c b/src/hardware/kingst-la2016/protocol.c
index 22d944110c92c48ba375099aba08e9b221489583..ecb21e3faa7af4c34eabccc3a6f85edf576f6a62 100644 (file)
--- a/src/hardware/kingst-la2016/protocol.c
+++ b/src/hardware/kingst-la2016/protocol.c
@@ -723,9 +723,11 @@ SR_PRIV int la2016_start_retrieval(const struct sr_dev_inst *sdi, libusb_transfe
        }
 
        to_read = devc->n_bytes_to_read;
-       if (to_read > LA2016_BULK_MAX)
-               to_read = LA2016_BULK_MAX;
-
+       /* choose a buffer size for all of the usb transfers */
+       if (to_read >= LA2016_USB_BUFSZ)
+               to_read = LA2016_USB_BUFSZ; /* multiple transfers */
+       else /* one transfer, make buffer size some multiple of LA2016_EP6_PKTSZ */
+               to_read = (to_read + (LA2016_EP6_PKTSZ-1)) & ~(LA2016_EP6_PKTSZ-1);
        buffer = g_try_malloc(to_read);
        if (!buffer) {
                sr_err("Failed to allocate %d bytes for bulk transfer", to_read);