Use a much longer callback timeout for USB writes on windows only as a last resort since cancellations work so poorly.
diff --git a/usbutils.c b/usbutils.c
index c893688..df51267 100644
--- a/usbutils.c
+++ b/usbutils.c
@@ -65,6 +65,7 @@
/* The safety timeout we use, cancelling async transfers on windows that fail
* to timeout on their own. */
#define WIN_CALLBACK_EXTRA 40
+#define WIN_WRITE_CBEXTRA 5000
#else
#define BFLSC_TIMEOUT_MS 300
#define BITFORCE_TIMEOUT_MS 200
@@ -2461,6 +2462,13 @@ usb_bulk_transfer(struct libusb_device_handle *dev_handle, int intinfo,
if ((endpoint & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_OUT) {
memcpy(buf, data, length);
ut.transfer->flags |= LIBUSB_TRANSFER_ADD_ZERO_PACKET;
+#ifdef WIN32
+ /* Writes on windows really don't like to be cancelled, but
+ * are prone to timeouts under heavy USB traffic, so make this
+ * a last resort cancellation delayed long after the write
+ * would have timed out on its own. */
+ callback_timeout += WIN_WRITE_CBEXTRA;
+#endif
}
USBDEBUG("USB debug: @usb_bulk_transfer(%s (nodev=%s),intinfo=%d,epinfo=%d,data=%p,length=%d,timeout=%u,mode=%d,cmd=%s,seq=%d) endpoint=%d", cgpu->drv->name, bool_str(cgpu->usbinfo.nodev), intinfo, epinfo, data, length, timeout, mode, usb_cmdname(cmd), seq, (int)endpoint);