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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 B33EAC433F5 for ; Mon, 6 Sep 2021 19:58:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9636B6069E for ; Mon, 6 Sep 2021 19:58:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243780AbhIFT7p (ORCPT ); Mon, 6 Sep 2021 15:59:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244388AbhIFT7n (ORCPT ); Mon, 6 Sep 2021 15:59:43 -0400 Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A3BEC061575 for ; Mon, 6 Sep 2021 12:58:38 -0700 (PDT) Received: by mail-io1-xd2a.google.com with SMTP id g9so9921273ioq.11 for ; Mon, 06 Sep 2021 12:58:38 -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=4jKC3FHzKHBCAnlV2/PSK1c4DpRsVjTTdfsdoygYbb4=; b=cY6QYaFpDCZJtp5tKnLfK0uaphhbqH2K9/5kBaf9eULECPvNH2o47Jd5uRNvq7Dblu Zmq7FhSN8Ih8F694W6cm+UiqOYqo+3rEhro8BtGO3UnuBy0Sfvw4fn8MCRlf3dL05agR PIwNbzHZKuf4mLDbRbawYMj1qFjHBCw8T7ZTcqSE6vmSJHJ+ON/fuadAoLfwzMf1GjfJ 7kLqPEhncOSxVJQTrLIih+c+ktk43fP2PJaSVtDzRCuVh8SrapLWJb60vnBklHbTn2b2 A4f46gv824+6etHj6Z8ZpJKyitiZnbotGYzy2XmXusXS+9dBAgaX+dAx5CtvLE7AhOfQ 6l6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=4jKC3FHzKHBCAnlV2/PSK1c4DpRsVjTTdfsdoygYbb4=; b=AX9uPy2H+2hjb/SrYZqbv3Wvy6r9+Bj+mLkEU1ONvY/7RTHOeOY0MMQjBLu9Mjnwwc R5kCBMqzR86wWTU9bGjbvxkBjA2tSuAEfFwHLkwiA2YdUy+AZt1Lr9j1CVI43Th1oX8L hL/0KJqEMc4jEmYHxJ3tqyNVeTfKF9rqsGC+vlCvJtLVnrqzbDooE2wam+xiQbl0Tira 4mdlo45hYgJ8Y7deysVQCiDEVAujZjZmIDQSoD87TQ00mWViaUNJJ5J32yp1HazIoyvF qiYXgzzgTwylKgHGasIj/H/q65UhM0RdYaxWltoBZdUBuNuIGUBAEzsf+0iIahg31tjK 09MQ== X-Gm-Message-State: AOAM533iIB4/sQV351MyU+bH9ueIJvyUDm7K8Lzk8MQDng8Y2wHxUK2I wYPZVa3Xo3631Zu7i8P3+dxJh2tIOFUCAttYQ9WEdg== X-Google-Smtp-Source: ABdhPJx3u2oJ0Fc1nRAkRhUH9xRAThEJHXD0P7O4XuDSF54J0Z8CpQV1r8tkxnvxrNSkipa2629NWh9Mpw7lzRY/Asg= X-Received: by 2002:a02:3846:: with SMTP id v6mr11926945jae.45.1630958317857; Mon, 06 Sep 2021 12:58:37 -0700 (PDT) MIME-Version: 1.0 References: <20210729183942.2839925-1-robdclark@gmail.com> <1a38a590-a64e-58ef-1bbf-0ae49c004d05@linaro.org> In-Reply-To: From: Amit Pundir Date: Tue, 7 Sep 2021 01:28:01 +0530 Message-ID: Subject: Re: [PATCH] drm/msm: Disable frequency clamping on a630 To: Rob Clark Cc: John Stultz , Caleb Connolly , Rob Clark , freedreno , Sai Prakash Ranjan , Jonathan Marek , David Airlie , linux-arm-msm , Sharat Masetty , Akhil P Oommen , dri-devel , Jordan Crouse , Stephen Boyd , Bjorn Andersson , Sean Paul , open list Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, 6 Sept 2021 at 21:54, Rob Clark wrote: > > On Mon, Sep 6, 2021 at 1:02 AM Amit Pundir wrote: > > > > On Sat, 4 Sept 2021 at 01:55, Rob Clark wrote: > > > > > > On Fri, Sep 3, 2021 at 12:39 PM John Stultz wrote: > > > > > > > > On Thu, Jul 29, 2021 at 1:49 PM Rob Clark wrote: > > > > > On Thu, Jul 29, 2021 at 1:28 PM Caleb Connolly > > > > > wrote: > > > > > > On 29/07/2021 21:24, Rob Clark wrote: > > > > > > > On Thu, Jul 29, 2021 at 1:06 PM Caleb Connolly > > > > > > > wrote: > > > > > > >> > > > > > > >> Hi Rob, > > > > > > >> > > > > > > >> I've done some more testing! It looks like before that patch ("drm/msm: Devfreq tuning") the GPU would never get above > > > > > > >> the second frequency in the OPP table (342MHz) (at least, not in glxgears). With the patch applied it would more > > > > > > >> aggressively jump up to the max frequency which seems to be unstable at the default regulator voltages. > > > > > > > > > > > > > > *ohh*, yeah, ok, that would explain it > > > > > > > > > > > > > >> Hacking the pm8005 s1 regulator (which provides VDD_GFX) up to 0.988v (instead of the stock 0.516v) makes the GPU stable > > > > > > >> at the higher frequencies. > > > > > > >> > > > > > > >> Applying this patch reverts the behaviour, and the GPU never goes above 342MHz in glxgears, losing ~30% performance in > > > > > > >> glxgear. > > > > > > >> > > > > > > >> I think (?) that enabling CPR support would be the proper solution to this - that would ensure that the regulators run > > > > > > >> at the voltage the hardware needs to be stable. > > > > > > >> > > > > > > >> Is hacking the voltage higher (although ideally not quite that high) an acceptable short term solution until we have > > > > > > >> CPR? Or would it be safer to just not make use of the higher frequencies on a630 for now? > > > > > > >> > > > > > > > > > > > > > > tbh, I'm not sure about the regulator stuff and CPR.. Bjorn is already > > > > > > > on CC and I added sboyd, maybe one of them knows better. > > > > > > > > > > > > > > In the short term, removing the higher problematic OPPs from dts might > > > > > > > be a better option than this patch (which I'm dropping), since there > > > > > > > is nothing stopping other workloads from hitting higher OPPs. > > > > > > Oh yeah that sounds like a more sensible workaround than mine . > > > > > > > > > > > > > > I'm slightly curious why I didn't have problems at higher OPPs on my > > > > > > > c630 laptop (sdm850) > > > > > > Perhaps you won the sillicon lottery - iirc sdm850 is binned for higher clocks as is out of the factory. > > > > > > > > > > > > Would it be best to drop the OPPs for all devices? Or just those affected? I guess it's possible another c630 might > > > > > > crash where yours doesn't? > > > > > > > > > > I've not heard any reports of similar issues from the handful of other > > > > > folks with c630's on #aarch64-laptops.. but I can't really say if that > > > > > is luck or not. > > > > > > > > > > Maybe just remove it for affected devices? But I'll defer to Bjorn. > > > > > > > > Just as another datapoint, I was just marveling at how suddenly smooth > > > > the UI was performing on db845c and Caleb pointed me at the "drm/msm: > > > > Devfreq tuning" patch as the likely cause of the improvement, and > > > > mid-discussion my board crashed into USB crash mode: > > > > [ 146.157696][ C0] adreno 5000000.gpu: CP | AHB bus error > > > > [ 146.163303][ C0] adreno 5000000.gpu: CP | AHB bus error > > > > [ 146.168837][ C0] adreno 5000000.gpu: RBBM | ATB bus overflow > > > > [ 146.174960][ C0] adreno 5000000.gpu: CP | HW fault | status=0x00000000 > > > > [ 146.181917][ C0] adreno 5000000.gpu: CP | AHB bus error > > > > [ 146.187547][ C0] adreno 5000000.gpu: CP illegal instruction error > > > > [ 146.194009][ C0] adreno 5000000.gpu: CP | AHB bus error > > > > [ 146.308909][ T9] Internal error: synchronous external abort: > > > > 96000010 [#1] PREEMPT SMP > > > > [ 146.317150][ T9] Modules linked in: > > > > [ 146.320941][ T9] CPU: 3 PID: 9 Comm: kworker/u16:1 Tainted: G > > > > W 5.14.0-mainline-06795-g42b258c2275c #24 > > > > [ 146.331974][ T9] Hardware name: Thundercomm Dragonboar > > > > Format: Log Type - Time(microsec) - Message - Optional Info > > > > Log Type: B - Since Boot(Power On Reset), D - Delta, S - Statistic > > > > S - QC_IMAGE_VERSION_STRING=BOOT.XF.2.0-00371-SDM845LZB-1 > > > > S - IMAGE_VARIANT_STRING=SDM845LA > > > > S - OEM_IMAGE_VERSION_STRING=TSBJ-FA-PC-02170 > > > > > > > > So Caleb sent me to this thread. :) > > > > > > > > I'm still trying to trip it again, but it does seem like db845c is > > > > also seeing some stability issues with Linus' HEAD. > > > > > > > > > > Caleb's original pastebin seems to have expired (or at least require > > > some sort of ubuntu login to access).. were the crashes he was seeing > > > also 'AHB bus error'? > > > > I can reproduce this hard crash > > https://www.irccloud.com/pastebin/Cu6UJntE/ and a gpu lockup > > https://www.irccloud.com/pastebin/6Ryd2Pug/ at times reliably, by > > running antutu benchmark on pocof1. > > > > Reverting 9bc95570175a ("drm/msm: Devfreq tuning") helps and I no > > longer see these errors. > > > > Complete dmesg for hardcrash https://pastebin.com/raw/GLZVQFQN > > > > Does antutu trigger this issue as easily on db845c? If no, does > db845c have pmic differences compared to pocof1 and Caleb's phone? Yes I can reproduce this hard crash with antutu on db845c as well with linux/master at 477f70cd2a67 ("Merge tag 'drm-next-2021-08-31-1' of git://anongit.freedesktop.org/drm/drm"). Dmesg: https://pastebin.com/raw/xXtvxk0G > > I think we may need some help from qcom here, but I'll go back and > look at older downstream kernels to see if I can find any evidence > that we need to limit how far we change the freq in a single step. > It's not clear to me if there is some physical constraint that the > driver needs to respect, or if we have some missing/incorrect > configuration for a630. IIRC the downstream kernel is letting the GMU > do more of the freq management, so it might be handling this case for > the kernel. But the GMU is a bit of a black box to me and I don't > have any docs, so just a guess. > > It would be helpful if someone who can repro this could try the > experiments I mentioned about increasing min_freq and/or decreasing > max_freq to limit the size of the freq change until the issue does not > happen. > > If we have to, we can merge this hack patch to disable freq clamping > on a630.. but that isn't really a fix. The root issue is a power > issue, 9bc95570175a just made it more likely to see the problem. > > BR, > -R > > > Regards, > > Amit Pundir > > > > > > > > If you have a reliable reproducer, I guess it would be worth seeing if > > > increasing the min_freq (ie. to limit how far we jump the freq in one > > > shot) "fixes" it? > > > > > > I guess I could check downstream kgsl to see if they were doing > > > something to increase freq in smaller increments.. I don't recall that > > > they were but it has been a while since I dug thru that code. And I > > > suppose downstream it could also be done in their custom tz governor. > > > > > > BR, > > > -R 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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 6276DC433EF for ; Mon, 6 Sep 2021 19:58:41 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2708B6069E for ; Mon, 6 Sep 2021 19:58:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2708B6069E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 82B6B89C19; Mon, 6 Sep 2021 19:58:39 +0000 (UTC) Received: from mail-io1-xd2c.google.com (mail-io1-xd2c.google.com [IPv6:2607:f8b0:4864:20::d2c]) by gabe.freedesktop.org (Postfix) with ESMTPS id B55D089C1C for ; Mon, 6 Sep 2021 19:58:38 +0000 (UTC) Received: by mail-io1-xd2c.google.com with SMTP id j18so9907342ioj.8 for ; Mon, 06 Sep 2021 12:58:38 -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=4jKC3FHzKHBCAnlV2/PSK1c4DpRsVjTTdfsdoygYbb4=; b=cY6QYaFpDCZJtp5tKnLfK0uaphhbqH2K9/5kBaf9eULECPvNH2o47Jd5uRNvq7Dblu Zmq7FhSN8Ih8F694W6cm+UiqOYqo+3rEhro8BtGO3UnuBy0Sfvw4fn8MCRlf3dL05agR PIwNbzHZKuf4mLDbRbawYMj1qFjHBCw8T7ZTcqSE6vmSJHJ+ON/fuadAoLfwzMf1GjfJ 7kLqPEhncOSxVJQTrLIih+c+ktk43fP2PJaSVtDzRCuVh8SrapLWJb60vnBklHbTn2b2 A4f46gv824+6etHj6Z8ZpJKyitiZnbotGYzy2XmXusXS+9dBAgaX+dAx5CtvLE7AhOfQ 6l6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=4jKC3FHzKHBCAnlV2/PSK1c4DpRsVjTTdfsdoygYbb4=; b=t/xgXjRYAcnaDCWnlWQYc6Hztpcajlr6SKh0NjdPDYyTky6EwYQJunUclCoeCI6IPm OIDJi0ny6FYqOdHjTbMS+hZhEnw9TmF/+WkJ8/RCtxJel5Ejk0xhaOcQ/zr+Yzr+2K0j eW09jwxi3RUMqY3xAjG6bdEDUz5U0sZjtEshOp1A7SoSwd5VgXj3lBb1S47dqTGe4r6s CfR5wdDKTIcURi/+4SMtBO5GkoPa1+BUbwmPD49ifCuNVxoxl+hNPCGF24ocAhGUndjh b2oAJE+0LPuAn3zTWzxxSepIwC6XQpootOMQUM9couuv5Iez69dTDHZvolBHwh+RB6JK NWSw== X-Gm-Message-State: AOAM531tJxxuGiFczaeYh4rYvIHG9VklA2ANubQcMGCarMFS/Ngtif5s tw4f2+21SacKZzg92Ld2OITf5qKjcD2pf/mUEpxr4Q== X-Google-Smtp-Source: ABdhPJx3u2oJ0Fc1nRAkRhUH9xRAThEJHXD0P7O4XuDSF54J0Z8CpQV1r8tkxnvxrNSkipa2629NWh9Mpw7lzRY/Asg= X-Received: by 2002:a02:3846:: with SMTP id v6mr11926945jae.45.1630958317857; Mon, 06 Sep 2021 12:58:37 -0700 (PDT) MIME-Version: 1.0 References: <20210729183942.2839925-1-robdclark@gmail.com> <1a38a590-a64e-58ef-1bbf-0ae49c004d05@linaro.org> In-Reply-To: From: Amit Pundir Date: Tue, 7 Sep 2021 01:28:01 +0530 Message-ID: Subject: Re: [PATCH] drm/msm: Disable frequency clamping on a630 To: Rob Clark Cc: John Stultz , Caleb Connolly , Rob Clark , freedreno , Sai Prakash Ranjan , Jonathan Marek , David Airlie , linux-arm-msm , Sharat Masetty , Akhil P Oommen , dri-devel , Jordan Crouse , Stephen Boyd , Bjorn Andersson , Sean Paul , open list Content-Type: text/plain; charset="UTF-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, 6 Sept 2021 at 21:54, Rob Clark wrote: > > On Mon, Sep 6, 2021 at 1:02 AM Amit Pundir wrote: > > > > On Sat, 4 Sept 2021 at 01:55, Rob Clark wrote: > > > > > > On Fri, Sep 3, 2021 at 12:39 PM John Stultz wrote: > > > > > > > > On Thu, Jul 29, 2021 at 1:49 PM Rob Clark wrote: > > > > > On Thu, Jul 29, 2021 at 1:28 PM Caleb Connolly > > > > > wrote: > > > > > > On 29/07/2021 21:24, Rob Clark wrote: > > > > > > > On Thu, Jul 29, 2021 at 1:06 PM Caleb Connolly > > > > > > > wrote: > > > > > > >> > > > > > > >> Hi Rob, > > > > > > >> > > > > > > >> I've done some more testing! It looks like before that patch ("drm/msm: Devfreq tuning") the GPU would never get above > > > > > > >> the second frequency in the OPP table (342MHz) (at least, not in glxgears). With the patch applied it would more > > > > > > >> aggressively jump up to the max frequency which seems to be unstable at the default regulator voltages. > > > > > > > > > > > > > > *ohh*, yeah, ok, that would explain it > > > > > > > > > > > > > >> Hacking the pm8005 s1 regulator (which provides VDD_GFX) up to 0.988v (instead of the stock 0.516v) makes the GPU stable > > > > > > >> at the higher frequencies. > > > > > > >> > > > > > > >> Applying this patch reverts the behaviour, and the GPU never goes above 342MHz in glxgears, losing ~30% performance in > > > > > > >> glxgear. > > > > > > >> > > > > > > >> I think (?) that enabling CPR support would be the proper solution to this - that would ensure that the regulators run > > > > > > >> at the voltage the hardware needs to be stable. > > > > > > >> > > > > > > >> Is hacking the voltage higher (although ideally not quite that high) an acceptable short term solution until we have > > > > > > >> CPR? Or would it be safer to just not make use of the higher frequencies on a630 for now? > > > > > > >> > > > > > > > > > > > > > > tbh, I'm not sure about the regulator stuff and CPR.. Bjorn is already > > > > > > > on CC and I added sboyd, maybe one of them knows better. > > > > > > > > > > > > > > In the short term, removing the higher problematic OPPs from dts might > > > > > > > be a better option than this patch (which I'm dropping), since there > > > > > > > is nothing stopping other workloads from hitting higher OPPs. > > > > > > Oh yeah that sounds like a more sensible workaround than mine . > > > > > > > > > > > > > > I'm slightly curious why I didn't have problems at higher OPPs on my > > > > > > > c630 laptop (sdm850) > > > > > > Perhaps you won the sillicon lottery - iirc sdm850 is binned for higher clocks as is out of the factory. > > > > > > > > > > > > Would it be best to drop the OPPs for all devices? Or just those affected? I guess it's possible another c630 might > > > > > > crash where yours doesn't? > > > > > > > > > > I've not heard any reports of similar issues from the handful of other > > > > > folks with c630's on #aarch64-laptops.. but I can't really say if that > > > > > is luck or not. > > > > > > > > > > Maybe just remove it for affected devices? But I'll defer to Bjorn. > > > > > > > > Just as another datapoint, I was just marveling at how suddenly smooth > > > > the UI was performing on db845c and Caleb pointed me at the "drm/msm: > > > > Devfreq tuning" patch as the likely cause of the improvement, and > > > > mid-discussion my board crashed into USB crash mode: > > > > [ 146.157696][ C0] adreno 5000000.gpu: CP | AHB bus error > > > > [ 146.163303][ C0] adreno 5000000.gpu: CP | AHB bus error > > > > [ 146.168837][ C0] adreno 5000000.gpu: RBBM | ATB bus overflow > > > > [ 146.174960][ C0] adreno 5000000.gpu: CP | HW fault | status=0x00000000 > > > > [ 146.181917][ C0] adreno 5000000.gpu: CP | AHB bus error > > > > [ 146.187547][ C0] adreno 5000000.gpu: CP illegal instruction error > > > > [ 146.194009][ C0] adreno 5000000.gpu: CP | AHB bus error > > > > [ 146.308909][ T9] Internal error: synchronous external abort: > > > > 96000010 [#1] PREEMPT SMP > > > > [ 146.317150][ T9] Modules linked in: > > > > [ 146.320941][ T9] CPU: 3 PID: 9 Comm: kworker/u16:1 Tainted: G > > > > W 5.14.0-mainline-06795-g42b258c2275c #24 > > > > [ 146.331974][ T9] Hardware name: Thundercomm Dragonboar > > > > Format: Log Type - Time(microsec) - Message - Optional Info > > > > Log Type: B - Since Boot(Power On Reset), D - Delta, S - Statistic > > > > S - QC_IMAGE_VERSION_STRING=BOOT.XF.2.0-00371-SDM845LZB-1 > > > > S - IMAGE_VARIANT_STRING=SDM845LA > > > > S - OEM_IMAGE_VERSION_STRING=TSBJ-FA-PC-02170 > > > > > > > > So Caleb sent me to this thread. :) > > > > > > > > I'm still trying to trip it again, but it does seem like db845c is > > > > also seeing some stability issues with Linus' HEAD. > > > > > > > > > > Caleb's original pastebin seems to have expired (or at least require > > > some sort of ubuntu login to access).. were the crashes he was seeing > > > also 'AHB bus error'? > > > > I can reproduce this hard crash > > https://www.irccloud.com/pastebin/Cu6UJntE/ and a gpu lockup > > https://www.irccloud.com/pastebin/6Ryd2Pug/ at times reliably, by > > running antutu benchmark on pocof1. > > > > Reverting 9bc95570175a ("drm/msm: Devfreq tuning") helps and I no > > longer see these errors. > > > > Complete dmesg for hardcrash https://pastebin.com/raw/GLZVQFQN > > > > Does antutu trigger this issue as easily on db845c? If no, does > db845c have pmic differences compared to pocof1 and Caleb's phone? Yes I can reproduce this hard crash with antutu on db845c as well with linux/master at 477f70cd2a67 ("Merge tag 'drm-next-2021-08-31-1' of git://anongit.freedesktop.org/drm/drm"). Dmesg: https://pastebin.com/raw/xXtvxk0G > > I think we may need some help from qcom here, but I'll go back and > look at older downstream kernels to see if I can find any evidence > that we need to limit how far we change the freq in a single step. > It's not clear to me if there is some physical constraint that the > driver needs to respect, or if we have some missing/incorrect > configuration for a630. IIRC the downstream kernel is letting the GMU > do more of the freq management, so it might be handling this case for > the kernel. But the GMU is a bit of a black box to me and I don't > have any docs, so just a guess. > > It would be helpful if someone who can repro this could try the > experiments I mentioned about increasing min_freq and/or decreasing > max_freq to limit the size of the freq change until the issue does not > happen. > > If we have to, we can merge this hack patch to disable freq clamping > on a630.. but that isn't really a fix. The root issue is a power > issue, 9bc95570175a just made it more likely to see the problem. > > BR, > -R > > > Regards, > > Amit Pundir > > > > > > > > If you have a reliable reproducer, I guess it would be worth seeing if > > > increasing the min_freq (ie. to limit how far we jump the freq in one > > > shot) "fixes" it? > > > > > > I guess I could check downstream kgsl to see if they were doing > > > something to increase freq in smaller increments.. I don't recall that > > > they were but it has been a while since I dug thru that code. And I > > > suppose downstream it could also be done in their custom tz governor. > > > > > > BR, > > > -R