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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F104C433FE for ; Tue, 1 Feb 2022 05:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231911AbiBAFav (ORCPT ); Tue, 1 Feb 2022 00:30:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230367AbiBAFaq (ORCPT ); Tue, 1 Feb 2022 00:30:46 -0500 Received: from mail-yb1-xb33.google.com (mail-yb1-xb33.google.com [IPv6:2607:f8b0:4864:20::b33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8453AC06173B for ; Mon, 31 Jan 2022 21:30:46 -0800 (PST) Received: by mail-yb1-xb33.google.com with SMTP id v186so47612264ybg.1 for ; Mon, 31 Jan 2022 21:30:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=5kydovGavYpv7Z8Qzla4H6f1AHt/32IxvvPG5ynaWbE=; b=U77UZ+D4xbTT9TJN9/zszI5V0tEXwMdM+BFvx6Nb9KJU883KTTg8RWJqW4u+rENsbc mTJr60YFHw5Cyrrca0pMlnzqqtKSvEDubI0G2fZza/uyEvwpK6LDHKbyuL1pAKlu+isx 5Rnhlftwp2yqp8HSPx5SIs3NWouiN3k6iuUSYGxj7wdtzs4LuWuXt7HF6nYvE8dm6UJf J1nVZTCZUchtA+Hnhbrnp4yi2zYEiIcOXsDJBByWDsZQcVGxuYwU+aPi9Twkd3NAAQyx 7zDPjux6Iu/hWafBsPTXIjefy75b3o6mwNorP1BcbZabndECDeiebZm9E9u4xH8uPY2J Pp4A== 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=5kydovGavYpv7Z8Qzla4H6f1AHt/32IxvvPG5ynaWbE=; b=G4PVvt3VX6od6+TPE8c/mqx2mLp+WjmSbHWj4FH1/9YE03K9iSn3MQf7yVNj9w6GvK p8MY6gFccsyn/C0XarLcBGb4w+58isJTFiT8bf3sMEzXbXUyV6R3wOOJpEytOltTBTiS QQA6JAtIdGRnn3JHn9304P2uTuH9IXbR9icCt4rUaBz73zRVikOp4s5fo9MrylyRKYwP NWPVPky1xjM+E5zIh1pWrY0AMp2eVHuMFOYhIq4BjnDnQ5ocPOA1uPSy5uPcgte5p0kF 1xhmxdwnibwvUIVpjE/h9KR08GdqzRALcacfjVIRoLUGRwfvI/IKlrlKJlrPIwpm9AfC T1FA== X-Gm-Message-State: AOAM53025f9qPC1eMk1t81EPl2XAIGKuO2+hCL9BySM2QIk2W6sd6vm0 cSDpHisOiViESOqtbv1ja+W2mTnnicV1XoOOIY/CwQ== X-Google-Smtp-Source: ABdhPJynKbsLj1UEZZnKfLzmdFbVdxNi6pGBmrFfyYXto1lhLijfs+2rVmbRV30Q7qVZQAskM2peIoEkaBltQtJKHlQ= X-Received: by 2002:a25:50c7:: with SMTP id e190mr33046695ybb.324.1643693445559; Mon, 31 Jan 2022 21:30:45 -0800 (PST) MIME-Version: 1.0 References: <20210929000735.585237-1-saravanak@google.com> <20210929000735.585237-2-saravanak@google.com> <7hk0efmfzo.fsf@baylibre.com> In-Reply-To: <7hk0efmfzo.fsf@baylibre.com> From: Saravana Kannan Date: Mon, 31 Jan 2022 21:30:09 -0800 Message-ID: Subject: Re: [PATCH v4 1/2] drivers: bus: simple-pm-bus: Add support for probing simple bus only devices To: Kevin Hilman Cc: Russell King , Neil Armstrong , Geert Uytterhoeven , Magnus Damm , Tony Lindgren , Catalin Marinas , Will Deacon , Damien Le Moal , Greg Kroah-Hartman , Ulf Hansson , Rob Herring , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-oxnas@groups.io, linux-renesas-soc@vger.kernel.org, linux-omap@vger.kernel.org, linux-riscv@lists.infradead.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 31, 2022 at 7:18 PM Kevin Hilman wrote: > > Hi Saravana, > > Saravana Kannan writes: > > > fw_devlink could end up creating device links for bus only devices. > > However, bus only devices don't get probed and can block probe() or > > sync_state() [1] call backs of other devices. To avoid this, probe these > > devices using the simple-pm-bus driver. > > > > However, there are instances of devices that are not simple buses (they get > > probed by their specific drivers) that also list the "simple-bus" (or other > > bus only compatible strings) in their compatible property to automatically > > populate their child devices. We still want these devices to get probed by > > their specific drivers. So, we make sure this driver only probes devices > > that are only buses. > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > Signed-off-by: Saravana Kannan > > Tested-by: Saravana Kannan > > Tested-by: Ulf Hansson > > This patch landed in stable/linux-5.10.y as commit d5f13bbb5104 and it > broke suspend/resume on at least one TI AM335x board I'm testing on: > upstream dts: arch/arm/boot/dts/am335x-icev2.dts, upstream defconfig: > arch/arm/configs/omap2plus_defconfig. > > Bisecting between vanilla v5.10 (good) and stable/linux-5.10.y (bad) > pointed me to this patch, and I confirmed that reverting just this patch > on top of stable/linux-5.10.y makes it work again. > > Also interesting, this same platform works fine on vanilla v5.15, which > also includes this patch. That suggests that either 1) this patch > should not have been backported to v5.10 stable or 2) there are some > other dependencies that are missing in v5.10. > > Since vanilla v5.10 works fine, I'm leaning towards (1), but if you have > any ideas for deps that need backporting, I'm happy to try. Oh wow! I didn't realize I made so many changes AFTER 5.10! Unless I'm doing something wrong with my git commands. $ git log v5.10..v5.15 --oneline -- drivers/of/property.c $ git log v5.10..v5.15 --oneline --author=saravanak -- drivers/base/ If you don't think I got my git command completely wrong, yeah, way too many patches are missing on 5.10. I'd go with the option of dropping this patch on 5.10. > I haven't debugged exactly where it's hanging yet, but, enabling > CONFIG_DEBUG_DRIVER=y, and suspending with "no_console_suspend" on the > command line, the last line before it hangs is: > > [ 28.129966] simple-pm-bus ocp: noirq power domain suspend > > Any ideas? I'd guess it's either a sync_state() happening too soon since some of the dependencies aren't tracked. Or some dependency cycle that'd be handled correctly if the rest of the patches were picked up. Yeah, a pretty broad/vague answer. -Saravana