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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E510C4332F for ; Wed, 4 May 2022 14:09:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346211AbiEDONI (ORCPT ); Wed, 4 May 2022 10:13:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351070AbiEDONH (ORCPT ); Wed, 4 May 2022 10:13:07 -0400 Received: from mail-ot1-f53.google.com (mail-ot1-f53.google.com [209.85.210.53]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4D60419A7; Wed, 4 May 2022 07:09:31 -0700 (PDT) Received: by mail-ot1-f53.google.com with SMTP id y14-20020a9d460e000000b00605ee347da1so965072ote.8; Wed, 04 May 2022 07:09:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=o53a8GmxnocjGIYplhPt9PwSDPQJ/OPLUJA/SSfS1HM=; b=l4mdAZsYZYqH0kJ3KVaHvWC3PKi+vV81qasjUiPGDIVe5F2dsje5nwVy6gjB08vz4j svFU4W+nCzjBb/oIfHUVaQKDtPFS8KRH1XiQSAGlDhUl9ArEmDbhoA95ZiZCcpWZuPtv DsEgNU87GWlewYFhHCqiOitDD4Cmnzo8gpvlcBalu76coNEfvzEmgf454Z3rAlTNS96V YNxtSvHFz1RB1eyqK+eV+4F9W8UQmLLjC1HUCK66XITq86D/HGWwip+eosKdZoK9mM5E sA6zTKNlPCGpBZCnPDlJJPUdT5OvNUU9Cf0fG/G4XpnjMOvzUJFIcPi4N+2xKSkpZF9V 49Jw== X-Gm-Message-State: AOAM532oJqCWpZ+FQPdMGgwvqv+YiSWmItAkUwrqURDkeEaQVANDovqC FkisG9hftbf8JamR2FEjbQ== X-Google-Smtp-Source: ABdhPJxtg9hxvR1IWm7xYdENP2YcZLWfPM1hpwSN0lI2GlIknHz/N+T7Lk6/cpY1Z6RkYt3IV4Uh2A== X-Received: by 2002:a05:6830:16c8:b0:606:2557:e324 with SMTP id l8-20020a05683016c800b006062557e324mr4010876otr.33.1651673370512; Wed, 04 May 2022 07:09:30 -0700 (PDT) Received: from robh.at.kernel.org (66-90-144-107.dyn.grandenetworks.net. [66.90.144.107]) by smtp.gmail.com with ESMTPSA id b18-20020aca2212000000b00325cda1ff8esm4374899oic.13.2022.05.04.07.09.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 May 2022 07:09:29 -0700 (PDT) Received: (nullmailer pid 1631408 invoked by uid 1000); Wed, 04 May 2022 14:09:29 -0000 Date: Wed, 4 May 2022 09:09:29 -0500 From: Rob Herring To: Daniels Umanovskis Cc: Richard Leitner - SKIDATA , "linux-usb@vger.kernel.org" , "devicetree@vger.kernel.org" Subject: Re: [PATCH 1/2] dt-bindings: usb: usb251xb: add documentation for reset-delay-us Message-ID: References: <20220426123329.775-1-du@axentia.se> <20220426123329.775-2-du@axentia.se> <75ed6e33-0d67-c50f-4d3a-7345d5f058b4@axentia.se> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, May 03, 2022 at 11:41:17AM +0200, Daniels Umanovskis wrote: > On 5/3/22 11:21 AM, Richard Leitner - SKIDATA wrote: > > What's the maximum timeout you've observed? > > > > I guess it would be the simpler and "better" approach to just increase > > the timeout in the driver (if it's not too much above the 500µs). > > I saw 800-820 us at most, and my initial fix internally was just to increase > the sleep duration in the driver. But it's an increase of over 50% and I > don't feel it makes sense to change the driver's behavior for thousands of > users with properly working chips, hence the configurable timeout for > out-of-spec batches like the one we had here. I expect more users to run > across such batches in the coming months. > > In an ideal world, we'd just trash these hubs that should have surely failed > factory QA, but with today's component shortage that's an unimaginable > luxury... The only solution that works here is increase the timeout in the driver. Are you going to tweak the dtb based on what batch the chip is from? No, that's not possible. Having worked in a chip company, I can tell you how they would fix it. Better testing? No, they'd change the documentation. Rob