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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 E8E89C433FE for ; Fri, 3 Sep 2021 20:24:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA81B60E77 for ; Fri, 3 Sep 2021 20:24:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350509AbhICUZx (ORCPT ); Fri, 3 Sep 2021 16:25:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350464AbhICUZw (ORCPT ); Fri, 3 Sep 2021 16:25:52 -0400 Received: from mail-wr1-x432.google.com (mail-wr1-x432.google.com [IPv6:2a00:1450:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB5C5C061757; Fri, 3 Sep 2021 13:24:51 -0700 (PDT) Received: by mail-wr1-x432.google.com with SMTP id g18so315546wrc.11; Fri, 03 Sep 2021 13:24:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=TVVpgjo5Cfaza682w5KWsOpwl1uwq/nsCC8e82zI314=; b=Rt8geQ7VCeNG5FbQLG/Jq3ZI2ZqvY7V9exoYMOKRRIjM2KDZhdKEHcPgMf+q0F32SY HEzLYxPXZ5jXzKdW3iHEE0We7krPXLol/7nM2840OZt4WprWlzUpnJFDayFLt2E0grYV 0t1GlyOxsxWyhWBCp5CtzuxQMtFUvkr/dB3CyiEgXufg13gSP+h5umq7hPb5GJkD8+Vj isowlzyY6TI9BNRMKLGN6sWZVtj/5EpGNK+M1KZBYPPNQFPSksXwYEpYKGY/SVQzyXoO Jtb9M/GjLuUwgk4nWh/BZcKG5EvkZT7QXDMWWWQ7jNnIynlFAHoh+nd+6BMVyO3Yhxh2 0plw== 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=TVVpgjo5Cfaza682w5KWsOpwl1uwq/nsCC8e82zI314=; b=qoIgv7QRzIWlTkajTISO3C1lP+WzIlIRWwUHZyalLVv9QqLbAKqArmBpIUPaA9Xt1B O4eyvx7zslAvPT+ojyBnQwFNgOpOtBzvpnfukcmQTprs/zI35Q+s2YlA4ryirzyYn2bs mwUPiXZKX3QxiKx42tdDQejUXzASe70ANzRr+Hw6BfzpicTd6VNN6yEr+xmY2Qgz0wIG Y6IOdRPdw3K850wvkdTdcBJPzFs2rK8sdwC88SV/o0HpZn45mgwFUJJcK/pChMMkTUEU MUiFeUs/+RjTVTMMRX/Vx7fzXx2ORbdjlMciAuYlyrvHaS5v/Rf0voLmI6yDugCYymo9 2fjw== X-Gm-Message-State: AOAM532lySkzvTI3a3sVjYtEEruM9dp+Ugxx1tRjZpKcfAjo1k7d+3G7 9AYtKharc6Kx+DsmQLSbZdh9D3JbbsZvPwMswzv4v+L8 X-Google-Smtp-Source: ABdhPJz2LkXMZvkKMZnpMYID0ppLFrezLyfGdDdSTKP3FE3h1lTjyVd7tUbeqw2d6AXKTgLzDhlA/m9dpTloDw2fsdw= X-Received: by 2002:a05:6000:178b:: with SMTP id e11mr800697wrg.151.1630700690229; Fri, 03 Sep 2021 13:24:50 -0700 (PDT) MIME-Version: 1.0 References: <20210729183942.2839925-1-robdclark@gmail.com> <1a38a590-a64e-58ef-1bbf-0ae49c004d05@linaro.org> In-Reply-To: From: Rob Clark Date: Fri, 3 Sep 2021 13:29:09 -0700 Message-ID: Subject: Re: [PATCH] drm/msm: Disable frequency clamping on a630 To: John Stultz Cc: 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-kernel@vger.kernel.org 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'? 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