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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 4373BC433F5 for ; Thu, 9 Sep 2021 14:11:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B71F611AD for ; Thu, 9 Sep 2021 14:11:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353244AbhIIOMf (ORCPT ); Thu, 9 Sep 2021 10:12:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350321AbhIIOMb (ORCPT ); Thu, 9 Sep 2021 10:12:31 -0400 Received: from mail-io1-xd2d.google.com (mail-io1-xd2d.google.com [IPv6:2607:f8b0:4864:20::d2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D2911C08EB2C for ; Thu, 9 Sep 2021 05:17:52 -0700 (PDT) Received: by mail-io1-xd2d.google.com with SMTP id b200so1950258iof.13 for ; Thu, 09 Sep 2021 05:17:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=rYmN9+Vy/Zm7v0RZi8m78PsGaMbXCo9rwM4fXnlFa0A=; b=jw+iTpcLGi33/KUcEaVR3lYwDq9++0Zt56YuT9/orXgQXI25hLKmgRmzW2toJi7myz JPbld8zzLLon+cNCj7SMJHWAl067f8z7RD/RvROUFdI3Ou9HjZc9T162pgu15ZOYJZWf 8l6XWBvHQpCKJinTzZt7rdtsbGzQav/fEejvqKQbrPDpfyb0sFGaBk0BRRnT7PFZbdPv yDVqfSiMT2ie32yRsY5ei1vNEx8mK2qHqgyP2v9nXFZ+u09F6NjF7dVD9o9Dow2NTDdo xk3EumusBusF2wvolA+8go4RMKS8aOVH48wEZotYmp2DTIahIZFdmmYTDp8UB7F2vQc+ wEzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rYmN9+Vy/Zm7v0RZi8m78PsGaMbXCo9rwM4fXnlFa0A=; b=NkS4PKZFBS701JnWvVb+xoDoIHlIx9dXLdbBzIMcaevbQc8ry0L2qQQ5xnsbqcIs8L PL7/nDT7fxwo1p7ZUHo+2D9gTAXqsGYOSANpe9U8oEhkh8bmJkQ7Ch/rn+1Gb4oNB4Al F+EZzNv64A4plPzwluPT8BLQdjvFrXemIpTdelolPLCx9L1a7uF4gzChJOSIYhsTn+8P cxq7GIMNBL6JzwTnfmrZgMpN2x4CtiV59X58uXccjd7i4Tumr5njbq6ApB3PBjJATYzW GCf0Yjpa555WlJ8ToScYSYLEvSjeSZasDouAm8hNMmDh2yaNd4w+UxqJFd3O5loeMH2x aB6Q== X-Gm-Message-State: AOAM5302ZF/bVr3RJsAYdoZeHBUr2h90VwzMGJzk25IBOhI0A7t176tv YliuBUVWu0aBKu80+j1Jk5fFaizo024dEzgHXCKVfw== X-Google-Smtp-Source: ABdhPJzzGnEJRhZfFJ5kL+XJ9LhYV5UeHMmZWo/JVUq5RLvA5TfAvwZJL681YJ5O4yJaKOgNEx7M/kGJZcKwTSrjL5c= X-Received: by 2002:a6b:3f02:: with SMTP id m2mr2358919ioa.136.1631189872259; Thu, 09 Sep 2021 05:17:52 -0700 (PDT) MIME-Version: 1.0 References: <8aa590be-6a9f-9343-e897-18e86ea48202@linaro.org> <6eefedb2-9e59-56d2-7703-2faf6cb0ca3a@codeaurora.org> <83ecbe74-caf0-6c42-e6f5-4887b3b534c6@linaro.org> <53d3e5b7-9dc0-a806-70e9-b9b5ff877462@codeaurora.org> In-Reply-To: From: Amit Pundir Date: Thu, 9 Sep 2021 17:47:16 +0530 Message-ID: Subject: Re: [PATCH] drm/msm: Disable frequency clamping on a630 To: Bjorn Andersson Cc: Akhil P Oommen , Caleb Connolly , Rob Clark , dri-devel , freedreno , linux-arm-msm , Rob Clark , Sean Paul , David Airlie , Daniel Vetter , Jordan Crouse , Jonathan Marek , Sai Prakash Ranjan , Sharat Masetty , open list , Stephen Boyd Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed, 8 Sept 2021 at 07:50, Bjorn Andersson wrote: > > On Mon 09 Aug 10:26 PDT 2021, Akhil P Oommen wrote: > > > On 8/9/2021 9:48 PM, Caleb Connolly wrote: > > > > > > > > > On 09/08/2021 17:12, Rob Clark wrote: > > > > On Mon, Aug 9, 2021 at 7:52 AM Akhil P Oommen > > > > wrote: > [..] > > > > > I am a bit confused. We don't define a power domain for gpu in dt, > > > > > correct? Then what exactly set_opp do here? Do you think this usleep is > > > > > what is helping here somehow to mask the issue? > > > The power domains (for cx and gx) are defined in the GMU DT, the OPPs in > > > the GPU DT. For the sake of simplicity I'll refer to the lowest > > > frequency (257000000) and OPP level (RPMH_REGULATOR_LEVEL_LOW_SVS) as > > > the "min" state, and the highest frequency (710000000) and OPP level > > > (RPMH_REGULATOR_LEVEL_TURBO_L1) as the "max" state. These are defined in > > > sdm845.dtsi under the gpu node. > > > > > > The new devfreq behaviour unmasks what I think is a driver bug, it > > > inadvertently puts much more strain on the GPU regulators than they > > > usually get. With the new behaviour the GPU jumps from it's min state to > > > the max state and back again extremely rapidly under workloads as small > > > as refreshing UI. Where previously the GPU would rarely if ever go above > > > 342MHz when interacting with the device, it now jumps between min and > > > max many times per second. > > > > > > If my understanding is correct, the current implementation of the GMU > > > set freq is the following: > > > - Get OPP for frequency to set > > > - Push the frequency to the GMU - immediately updating the core clock > > > - Call dev_pm_opp_set_opp() which triggers a notify chain, this winds > > > up somewhere in power management code and causes the gx regulator level > > > to be updated > > > > Nope. dev_pm_opp_set_opp() sets the bandwidth for gpu and nothing else. We > > were using a different api earlier which got deprecated - > > dev_pm_opp_set_bw(). > > > > On the Lenovo Yoga C630 this is reproduced by starting alacritty and if > I'm lucky I managed to hit a few keys before it crashes, so I spent a > few hours looking into this as well... > > As you say, the dev_pm_opp_set_opp() will only cast a interconnect vote. > The opp-level is just there for show and isn't used by anything, at > least not on 845. > > Further more, I'm missing something in my tree, so the interconnect > doesn't hit sync_state, and as such we're not actually scaling the > buses. So the problem is not that Linux doesn't turn on the buses in > time. > > So I suspect that the "AHB bus error" isn't saying that we turned off > the bus, but rather that the GPU becomes unstable or something of that > sort. > > > Lastly, I reverted 9bc95570175a ("drm/msm: Devfreq tuning") and ran > Aquarium for 20 minutes without a problem. I then switched the gpu > devfreq governor to "userspace" and ran the following: > > while true; do > echo 257000000 > /sys/class/devfreq/5000000.gpu/userspace/set_freq > echo 710000000 > /sys/class/devfreq/5000000.gpu/userspace/set_freq > done > > It took 19 iterations of this loop to crash the GPU. Ack. With your above script, I can reproduce a crash too on db845c (A630) running v5.14. I didn't get any crash log though and device just rebooted to USB crash mode. And same crash on RB5 (A650) too https://hastebin.com/raw/ejutetuwun > > So the problem doesn't seem to be Rob's change, it's just that prior to > it the chance to hitting it is way lower. Question is still what it is > that we're triggering. > > Regards, > Bjorn