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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA0D9C433FE for ; Fri, 5 Nov 2021 22:33:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC35D6124A for ; Fri, 5 Nov 2021 22:33:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233380AbhKEWfr (ORCPT ); Fri, 5 Nov 2021 18:35:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230054AbhKEWfn (ORCPT ); Fri, 5 Nov 2021 18:35:43 -0400 Received: from mail-oi1-x22a.google.com (mail-oi1-x22a.google.com [IPv6:2607:f8b0:4864:20::22a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E541AC061714 for ; Fri, 5 Nov 2021 15:33:02 -0700 (PDT) Received: by mail-oi1-x22a.google.com with SMTP id o83so16777028oif.4 for ; Fri, 05 Nov 2021 15:33:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:in-reply-to:references:from:user-agent:date:message-id :subject:to:cc; bh=fWPW6vOrV4yWuNKQyKDDkLamXrngpvFNOzlcY43dNqs=; b=iKVG85gppzXqEaEOcL5Bb84m05PjYOdlnIwqPMXq+hWd3vGImllScnpAoM8rou02x6 zYzmGPkKPG7RowxQPg4xyPG3c/FKplaDd2p/I4ccOzLnNlzFKWulOb4CUOHAjMOZBCG/ axL+CUfZ9a8YWytneRUIm9D4Wx2ZZB7f5YCZg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:in-reply-to:references:from :user-agent:date:message-id:subject:to:cc; bh=fWPW6vOrV4yWuNKQyKDDkLamXrngpvFNOzlcY43dNqs=; b=ZNn85Ve1sOlsUCbGyIHBNtjBOv7jzK2S9HzRd+X6utskPGpHh08ZzM1CJbmiNu6E1F kfNOEC47iAGcBpFpcMb2gJbmPlrvMsG1wGxyg0fh2mip7rviRXFIEJWjjnQne2xRZOhK LJtZKAoWHc5KaQ2tsHjXL75tXeKAmbSpPeq9NGdHtwcDLDgsx4li+EOuyG1y05QqFKN5 RX5KixdLWVHJSacbrYNeIBKJBb/mVByyFpWc6vTDSCQNmpO39VG9QNP+Aq3uLsnta/xz +ilTvtbhr6wctBzSvLAvTUSUUMVIWJMfUekXPaVvEJCp1SX/0r+tbUEutPzPaWYXxN2R RZwQ== X-Gm-Message-State: AOAM531lL6O/HnKzfPmofnxNgIOecU9Vr/A4mxpjH/nSbk0dbxZSmrJd LKnIn+h8WDQHClRZLS1PkqgJs0CYA4vOtE4K9cZ+tg== X-Google-Smtp-Source: ABdhPJz+sZay+XktcSS+5myteHfFnaSYRjh0L2fXVqz51OpDz37VcMg34X0qvr4jMDBdhRGzkOJ7h2s7RmQz9/39vB0= X-Received: by 2002:a05:6808:a96:: with SMTP id q22mr16520113oij.164.1636151582339; Fri, 05 Nov 2021 15:33:02 -0700 (PDT) Received: from 753933720722 named unknown by gmailapi.google.com with HTTPREST; Fri, 5 Nov 2021 15:33:01 -0700 MIME-Version: 1.0 In-Reply-To: References: <1636133291-10551-1-git-send-email-quic_khsieh@quicinc.com> From: Stephen Boyd User-Agent: alot/0.9.1 Date: Fri, 5 Nov 2021 15:33:01 -0700 Message-ID: Subject: Re: [PATCH] drm/msm/dp: do not initialize phy until plugin interrupt received To: Bjorn Andersson , Kuogee Hsieh Cc: robdclark@gmail.com, sean@poorly.run, vkoul@kernel.org, daniel@ffwll.ch, airlied@linux.ie, agross@kernel.org, dmitry.baryshkov@linaro.org, quic_abhinavk@quicinc.com, aravindh@codeaurora.org, freedreno@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Kuogee Hsieh Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Quoting Bjorn Andersson (2021-11-05 10:48:37) > On Fri 05 Nov 10:28 PDT 2021, Kuogee Hsieh wrote: > > > From: Kuogee Hsieh > > > > Combo phy supports both USB and DP simultaneously. There may has a > > possible conflict during phy initialization phase between USB and > > DP driver which may cause USB phy timeout when USB tries to power > > up its phy. This patch has the DP driver not initialize its phy > > during DP driver initialization phase. Instead DP driver only enable > > required regulators and clocks so that it is able to receive HPD > > interrupts after completion of initialization phase. DP driver will > > initialize its phy when HPD plug-in interrupt received. > > Is this a hardware requirement, or is this a issue with the current > implementation of the QMP combo phy driver? We should not hack up the DP > driver to circumvent the latter. > > Also, I don't suppose there's anything here that prevents the HPD to > come before the USB PHY is powered up? Even though that seems less > likely in practice... > > > This patch also provides a positive side effects which balance regulator > > enable count since regulator only enabled at initialize phase and resume > > and disabled at followed suspend. > > > > Is this something that needs to be fixed separately, so that it can be > backported to stable kernels? Agreed. Please split the regulator balance problem from the DP initialization delay.