[PATCH 1/3] hw/usb/canokey: Fix CCID ZLP

[Hongren (Zenithal) Zheng]

CCID could send zero-length packet (ZLP)
if we invoke two data_in, two packets would be concated
and we could not distinguish them.

The CANOKEY_EMU_EP_CTAPHID is exported from canokey-qemu.h

Reported-by: MkfsSion <myychina28759@gmail.com>
Signed-off-by: Hongren (Zenithal) Zheng <i@zenithal.me>
---
 hw/usb/canokey.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/hw/usb/canokey.c b/hw/usb/canokey.c
index 4a08b1cbd7..86548923eb 100644
--- a/hw/usb/canokey.c
+++ b/hw/usb/canokey.c
@@ -109,11 +109,10 @@ int canokey_emu_transmit(
      * Note: this is a quirk for CanoKey CTAPHID
      * because it calls multiple emu_transmit in one device_loop
      * but w/o data_in it would stuck in device_loop
-     * This has no side effect for CCID as it is strictly
-     * OUT then IN transfer
-     * However it has side effect for Control transfer
+     * This has side effect for CCID since CCID can send ZLP
+     * This also has side effect for Control transfer
      */
-    if (ep_in != 0) {
+    if (ep_in == CANOKEY_EMU_EP_CTAPHID) {
         canokey_emu_data_in(ep_in);
     }
     return 0;
-- 
2.35.1