Bluetooth: btusb: Fix not handling ZPL/short-transfer

Requesting transfers of the exact same size of wMaxPacketSize may result
in ZPL/short-transfer since the USB stack cannot handle it as we are
limiting the buffer size to be the same as wMaxPacketSize.

Also, in terms of throughput this change has the same effect to
interrupt endpoint as 290ba200815f "Bluetooth: Improve USB driver throughput
by increasing the frame size" had for the bulk endpoint, so users of the
advertisement bearer (e.g. BT Mesh) may benefit from this change.

Fixes: 5e23b923da03 ("[Bluetooth] Add generic driver for Bluetooth USB devices")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Kiran K <kiran.k@intel.com>

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index d9286feacef8ca6f2f72add06138565490644891..6c9c761d5b93a8c7505b348b5d7b3caf9f69c9cb 100644 (file)
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -1345,7 +1345,10 @@ static int btusb_submit_intr_urb(struct hci_dev *hdev, gfp_t mem_flags)
        if (!urb)
                return -ENOMEM;
 
-       size = le16_to_cpu(data->intr_ep->wMaxPacketSize);
+       /* Use maximum HCI Event size so the USB stack handles
+        * ZPL/short-transfer automatically.
+        */
+       size = HCI_MAX_EVENT_SIZE;
 
        buf = kmalloc(size, mem_flags);
        if (!buf) {