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=-5.8 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 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 648EAC433E6 for ; Sat, 23 Jan 2021 23:22:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29D8122CF7 for ; Sat, 23 Jan 2021 23:22:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726348AbhAWXWK (ORCPT ); Sat, 23 Jan 2021 18:22:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725932AbhAWXWH (ORCPT ); Sat, 23 Jan 2021 18:22:07 -0500 Received: from mail-lf1-x133.google.com (mail-lf1-x133.google.com [IPv6:2a00:1450:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 222A1C0613D6 for ; Sat, 23 Jan 2021 15:21:26 -0800 (PST) Received: by mail-lf1-x133.google.com with SMTP id o10so12648486lfl.13 for ; Sat, 23 Jan 2021 15:21:26 -0800 (PST) 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=qagM0m0Ne7exzQc7D+nxb7xrSis3ioyasnLHWjTOwEI=; b=aNCoUPOtfcenk0mjU7bVGiHXANroTF3BoeOZ9uWUGlcT3BjbQV/0btCzBpPtHMiyry zkul8ohQy08JT2n/bLJw5HpSVrp3YZHc6GYSqjImAO/y0PC22QRap2SGG9f1Ztnk8HUT bmkalV0qPWaj9/tCGpUxxHGB9H4/tzkJjK4ze+xlkqUobayE3ekw3+BvReawNUAfsbIE KMkwcjGFWh+1PybLkfHmSdhcuwNUpqdMKgeTxBVoJz8C5DKlBlDd4bdeIIGAIyG6QkQ0 hZFg1jTubjg6sCLCETYy9wP9GzVnA4CIa6WKfAFXWT5zWRM9UazSjkIccehSDlF8BgPN uzhQ== 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=qagM0m0Ne7exzQc7D+nxb7xrSis3ioyasnLHWjTOwEI=; b=U1nSlPjtbtYUJDX2CLLUkL5lo7htaBt2ASU2rNH0dmPyRIz1R3ROoEGghuRhtBm1y+ ezbk0Zt/arW71EkxBHI5bd4B78qQakgb+VB3T5QAlM5NbI9HOc6TET2a/trQhkmWeV/B W8M9xSxnv/pe6Qlc6+eLJWy42lxGtPLxayJ+Rcpt66HBhE8xEoIZTkxaCZ+/SCLiLZ2B zRWOXSf/RkydXNFAaSqVM4/7WPt8cBK8EDv4slQop2V+edKj4P+F0asWrFxX+TXGG6WK N/bFE3efaGnAZN4xIdA1meNpB7NLnmZXmawNE7SU7uozv2cS89ZnMdiEXUXItEUPjkwI I5lw== X-Gm-Message-State: AOAM531NOdYkDoK5YqaST2m+UOJbZjSXPMXXeUy/DmgTcW9KXcKS531A wcceqEZxg6Zq3A8CJWICcKbSJ1GbcX0qH09Ps0QEog== X-Google-Smtp-Source: ABdhPJzxdSjDvwqayFyUDH3wXFFC6QI7cOiEKiMhgJgzYqRLFq9Q7Fi5AJIcFuHywIu0M6AdkwPanKezurMEY1x3NlM= X-Received: by 2002:a19:8bc6:: with SMTP id n189mr1073086lfd.291.1611444084447; Sat, 23 Jan 2021 15:21:24 -0800 (PST) MIME-Version: 1.0 References: <20210119124622.9490-1-mike.looijmans@topic.nl> <20210119124622.9490-2-mike.looijmans@topic.nl> <20210123153511.1802a15a@archlinux> In-Reply-To: <20210123153511.1802a15a@archlinux> From: Linus Walleij Date: Sun, 24 Jan 2021 00:21:13 +0100 Message-ID: Subject: Re: [PATCH v6 2/2] iio: accel: Add support for the Bosch-Sensortec BMI088 To: Jonathan Cameron Cc: Mike Looijmans , linux-iio , Dan Robertson , =?UTF-8?B?R2HDq3RhbiBBbmRyw6k=?= , Jonathan Bakker , Lars-Peter Clausen , Peter Meerwald-Stadler , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 23, 2021 at 4:35 PM Jonathan Cameron wrote: > [Me] > > Next, I think it is better to let suspend/resume, i.e. system PM > > reuse runtime PM since you're implementing that. This is why > > we invented PM runtime force resume and force suspend. > > Here the driver is turning more off for full suspend than in the > runtime path. If that results in significant extra delay then > it's not appropriate to have that in the runtime suspend path. I see the point. The resume path calls bmi088_accel_enable() which incurs a 5ms delay. The runtime resume path incurs a 1 ms delay. The runtime autosuspend kicks in after 2 ms. > Maybe the simplification of not doing the deeper power saving > mode is worth the extra power cost or extra delay, but > I'm not yet convinced. I would personally set the autosuspend to ~20ms and just use one path and take a hit of 5 ms whenever we go down between measures if it is a system that is for human interaction, but for control systems this more complex set-up may be better for response latencies. The current approach may be better tuned to perfection and we are all perfectionists :D I'm just worrying a little about bugs and maintainability. Yours, Linus Walleij