* avoid interrupt storms we'll wait before retrying if we've got
* several NAKs. If we didn't do this we'd retry directly from the
* interrupt handler and could end up quickly getting another
- * interrupt (another NAK), which we'd retry.
+ * interrupt (another NAK), which we'd retry. Note that we do not
+ * delay retries for IN parts of control requests, as those are expected
+ * to complete fairly quickly, and if we delay them we risk confusing
+ * the device and cause it issue STALL.
*
* Note that in DMA mode software only gets involved to re-send NAKed
* transfers for split transactions, so we only need to apply this
qtd->error_count = 0;
qtd->complete_split = 0;
qtd->num_naks++;
- qtd->qh->want_wait = qtd->num_naks >= DWC2_NAKS_BEFORE_DELAY;
+ qtd->qh->want_wait = qtd->num_naks >= DWC2_NAKS_BEFORE_DELAY &&
+ !(chan->ep_type == USB_ENDPOINT_XFER_CONTROL &&
+ chan->ep_is_in);
dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_NAK);
goto handle_nak_done;
}