From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69807C4360C for ; Fri, 27 Sep 2019 15:57:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4897C217D9 for ; Fri, 27 Sep 2019 15:57:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727416AbfI0P5m (ORCPT ); Fri, 27 Sep 2019 11:57:42 -0400 Received: from muru.com ([72.249.23.125]:34662 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727273AbfI0P5m (ORCPT ); Fri, 27 Sep 2019 11:57:42 -0400 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id A59878022; Fri, 27 Sep 2019 15:58:13 +0000 (UTC) Date: Fri, 27 Sep 2019 08:57:38 -0700 From: Tony Lindgren To: Yegor Yefremov Cc: linux-omap@vger.kernel.org, vkoul@kernel.org, Bin Liu , linux-usb Subject: Re: musb: cppi41: broken high speed FTDI functionality when connected to musb directly Message-ID: <20190927155738.GF5610@atomide.com> References: <20190927151935.GD5610@atomide.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190927151935.GD5610@atomide.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org * Tony Lindgren [190927 15:20]: > * Yegor Yefremov [190927 12:31]: > > On Fri, Sep 27, 2019 at 10:18 AM Yegor Yefremov > > wrote: > > > > > > I was porting my system from 3.18/4.2 to 5.3. During this process I > > > noticed that FT4232 that is attached directly to musb is not working > > > correctly when opened for the first time: tx is working but nothing > > > can be received. On the second opening everything is working fine. > > > When the same chip is connected via a USB hub - everything is working > > > from the very beginning. > > > > > > I could reproduce this issue using BeagleBone Black with omap2plus_defconfig. > > > > > > # lsusb -t > > > +/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=musb-hdrc/1p, 480M > > > |__ Port 1: Dev 2, If 0, Class=, Driver=ftdi_sio, 480M > > > |__ Port 1: Dev 2, If 1, Class=, Driver=ftdi_sio, 480M > > > |__ Port 1: Dev 2, If 2, Class=, Driver=ftdi_sio, 480M > > > |__ Port 1: Dev 2, If 3, Class=, Driver=ftdi_sio, 480M > > > > > > git bisect revealed the following: > > > > > > fdea2d09b997ba4c86e7a707a5fac87c305f2131 is the first bad commit > > > commit fdea2d09b997ba4c86e7a707a5fac87c305f2131 > > > Author: Tony Lindgren > > > Date: Wed Aug 31 07:19:59 2016 -0700 > > > > > > dmaengine: cppi41: Add basic PM runtime support > > > > > > Let's keep the device enabled between cppi41_dma_issue_pending() > > > and dmaengine_desc_get_callback_invoke() and rely on the PM runtime > > > autoidle timeout elsewhere. > > > > > > As the PM runtime is for whole device, not for each channel, > > > we need to queue pending transfers if the device is PM runtime > > > suspended. Then we start the pending transfers in PM runtime > > > resume. > > > > > > Signed-off-by: Tony Lindgren > > > Signed-off-by: Vinod Koul > > > > > > :040000 040000 8cf92c09083541dfdee01cc2973e73ef520f4fb1 > > > a03c1a7ba8e723f7b503733c46edaa4141483265 M drivers > > > > > > Any idea? > > > > The problems can be reproduced with other FTDI chips like FT232R. > > > > Invoking "minicom -D /dev/ttyUSB0" and typing some characters is > > enough to reproduce the issue (just in case, hw flow control should be > > disabled). > > > > cp210x based converter is working without an issue. So only FTDI chips > > are affected so far. > > Hmm OK. Maybe this could be an issue where the FTDI chip takes > longer to enumerate and cppi41 is already suspended by then? > > At least we had a similar issue with commit ae4a3e028bb8 > ("dmaengine: cppi41: Fix runtime PM timeouts with USB mass > storage"). Looks like I'm unable to reproduce this with bbb and FT232R USB UART. I tried v5.3 with omap2plus_defconfig, then boot, load musb and ftdi-sio modules, then connect ftdi directly to bbb, and then run "minicom -D /dev/ttyUSB0" on bbb and it works just fine for me. I tried also rebooting the device inbetween in case it only happens on the first connect after boot but still no luck reproducing. Maybe try adding some debug prints to cppi41_runtime_suspend() and cppi41_runtime_resume() to see if gets runtime suspended too early? Regards, Tony