Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754888AbcDKM6Q (ORCPT ); Mon, 11 Apr 2016 08:58:16 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:49182 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754559AbcDKM6O (ORCPT ); Mon, 11 Apr 2016 08:58:14 -0400 Subject: Re: [PATCH 1/2] usb: dwc3: core: Introduce dwc3_device_reinit() To: Felipe Balbi , John Youn References: <1458133551-3071-1-git-send-email-rogerq@ti.com> <1458133551-3071-2-git-send-email-rogerq@ti.com> <87r3fah8h3.fsf@intel.com> <87lh5ih6hs.fsf@intel.com> <56EC5452.8030509@synopsys.com> <56F03FD7.30202@synopsys.com> <874mbzyq1l.fsf@intel.com> <56F3376E.8050305@synopsys.com> <87d1qkxtbb.fsf@intel.com> <56FC1E92.60403@synopsys.com> <56FD2E13.2010903@ti.com> <87r3eqg1us.fsf@intel.com> <57021CB9.3090803@ti.com> <87inzx7q0l.fsf@intel.com> <570B9A84.1020607@ti.com> <8737qsnw9x.fsf@intel.com> CC: "nsekhar@ti.com" , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Shankar, Abhishek" , "B, Ravi" From: Roger Quadros Message-ID: <570B9F5F.3050207@ti.com> Date: Mon, 11 Apr 2016 15:58:07 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <8737qsnw9x.fsf@intel.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2070 Lines: 56 On 11/04/16 15:51, Felipe Balbi wrote: > > Hi, > > Roger Quadros writes: > > > >>> I don't have this text anywhere so I don't know. Is this something TI >>> came up with or Synopsys ? Unless I can see a document (preferrably from >>> Synopsys) stating this, I can't really accept $subject. >> >> OK. I'll try to find out if there is an official document about this. >> >>> >>> Another question is: if all it takes is an extra SoftReset, why don't we >>> just reset it during probe() if max_speed < SUPER and we're running on >>> rev < 2.20a ? BTW, which revision of the IP is on AM57x/DRA7x ? >> >> The issue might happen on any Run/Stop transition so not sure if doing it >> SoftReset just at probe fixes anything. >> >> On DRA7x it is rev 2.02a. > > oh, same block as OMAP5 ES2.0 :-( > >>>>> question is, then: How are you sure that resetting the device actually >>>>> solves the issue ? Did you really hit the metastability problem and >>>>> noted that it works after a soft-reset ? How did you verify that >>>> >>>> I don't know if it solves the issue or not. It was suggested by >>>> Synopsis to TI's silicon team. >>> >>> now that's a bummer ;-) >>> >>>> I never hit the metastability problem detection condition in my >>>> overnight tests (i.e. LTDB_LINK_STATE != 4). >>> >>> overnight is not enough. You need to keep this running for weeks. >> >> how many weeks is acceptable for you? I can run for that long, no problem. >> And what if the issue doesn't happen in that time frame, would you still >> consider this case? > > Well, there's always the possibility we have never triggered the issue > to start with :-) What happens if you remove the the current workaround, > set maximum-speed to high-speed and constantly toggle run/stop bit > (there's a soft-connect file under the UDC's directory in sysfs). Can > you ever cause the problems ? I had tried a with max-speed set to high-speed and a script that just reloads g_zero. That should toggle Run/Stop right? Running this overnight didn't cause any problems. cheers, -roger