Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965112AbaLMFNK (ORCPT ); Sat, 13 Dec 2014 00:13:10 -0500 Received: from mail-la0-f44.google.com ([209.85.215.44]:63608 "EHLO mail-la0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750760AbaLMFNI (ORCPT ); Sat, 13 Dec 2014 00:13:08 -0500 MIME-Version: 1.0 Date: Sat, 13 Dec 2014 10:43:04 +0530 Message-ID: Subject: query on DWC3 From: sundeep subbaraya To: "balbi@ti.com" Cc: "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Felipe, In DWC3 driver, for three stage Control OUT transfer there is a check: else if (!IS_ALIGNED(req->request.length, dep->endpoint.maxpacket) && (dep->number == 0)) {. } I understand that we check for alignment of sizes and if not we prepare trb with maxpacket and enable interrupt on short packet. In databook I could not find anything related to this, it talks only about addresses should be aligned. In Control transfer programming model there is no difference between Control OUT or IN transfer, if three stage transfer - prepare trb with length wLength. Initially I followed this and not able to receive data on EP0 OUT.:( .After adding the above check it is working. Please help me to understand why we do this? Thank in advance, Sundeep.B.S. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/