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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 3B4DCC4363D for ; Fri, 2 Oct 2020 18:27:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC40D20758 for ; Fri, 2 Oct 2020 18:27:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="wZBl+igt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387688AbgJBS1x (ORCPT ); Fri, 2 Oct 2020 14:27:53 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:41104 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725991AbgJBS1x (ORCPT ); Fri, 2 Oct 2020 14:27:53 -0400 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id EDA172A2; Fri, 2 Oct 2020 20:27:49 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1601663270; bh=CL5QKaTSsMb6uOSyPBGvu8YxIVCGyjDzLHUX8tgBwBo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wZBl+igtGmdH/uD5j0bBHyFKsKHD1i3MF6nT/2m0C41oytNOndqqNSI52IuRpkpob 5SWLocVoXdmw9CB6WlWHTFqUTPs/mRBn8zSnn/tdaGNGgj7LtbOR+itEoKEq39jm6m PIhzDqlranh+Agk1ENnGnuqAdauSdSPdOQcZ8iOI= Date: Fri, 2 Oct 2020 21:27:12 +0300 From: Laurent Pinchart To: Saravana Kannan Cc: Rob Herring , Frank Rowand , Geert Uytterhoeven , Greg Kroah-Hartman , Grygorii Strashko , linux-omap , "open list:THERMAL" , Peter Ujfalusi , "Rafael J. Wysocki" , Tomi Valkeinen , Tony Lindgren , Ulf Hansson , Android Kernel Team , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path Message-ID: <20201002182712.GF3933@pendragon.ideasonboard.com> References: <20201001225952.3676755-1-saravanak@google.com> <20201002175423.GE3933@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org Hi Saravana, On Fri, Oct 02, 2020 at 10:58:55AM -0700, Saravana Kannan wrote: > On Fri, Oct 2, 2020 at 10:55 AM Laurent Pinchart wrote: > > On Fri, Oct 02, 2020 at 10:51:51AM -0700, Saravana Kannan wrote: > > > On Fri, Oct 2, 2020 at 7:08 AM Rob Herring wrote: > > > > On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan wrote: > > > > > > > > > > When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when > > > > > adding all top level devices") optimized the fwnode parsing when all top > > > > > level devices are added, it missed out optimizing this for platform > > > > > where the top level devices are added through the init_machine() path. > > > > > > > > > > This commit does the optimization for all paths by simply moving the > > > > > fw_devlink_pause/resume() inside of_platform_default_populate(). > > > > > > > > > > Reported-by: Tomi Valkeinen > > > > > Signed-off-by: Saravana Kannan > > > > > --- > > > > > drivers/of/platform.c | 19 +++++++++++++++---- > > > > > 1 file changed, 15 insertions(+), 4 deletions(-) > > > > > > > > > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > > > > > index 071f04da32c8..79972e49b539 100644 > > > > > --- a/drivers/of/platform.c > > > > > +++ b/drivers/of/platform.c > > > > > @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root, > > > > > const struct of_dev_auxdata *lookup, > > > > > struct device *parent) > > > > > { > > > > > - return of_platform_populate(root, of_default_bus_match_table, lookup, > > > > > - parent); > > > > > + int ret; > > > > > + > > > > > + /* > > > > > + * fw_devlink_pause/resume() are only safe to be called around top > > > > > + * level device addition due to locking constraints. > > > > > + */ > > > > > + if (!root) > > > > > + fw_devlink_pause(); > > > > > + > > > > > + ret = of_platform_populate(root, of_default_bus_match_table, lookup, > > > > > + parent); > > > > > > > > of_platform_default_populate() vs. of_platform_populate() is just a > > > > different match table. I don't think the behavior should otherwise be > > > > different. > > > > > > > > There's also of_platform_probe() which has slightly different matching > > > > behavior. It should not behave differently either with respect to > > > > devlinks. > > > > > > So I'm trying to do this only when the top level devices are added for > > > the first time. of_platform_default_populate() seems to be the most > > > common path. For other cases, I think we just need to call > > > fw_devlink_pause/resume() wherever the top level devices are added for > > > the first time. As I said in the other email, we can't add > > > fw_devlink_pause/resume() by default to of_platform_populate(). > > > > > > Do you have other ideas for achieving "call fw_devlink_pause/resume() > > > only when top level devices are added for the first time"? > > > > I'm not an expert in this domain, but before investigating it, would you > > be able to share a hack patch that implements this (in the most simple > > way) to check if it actually fixes the delays I experience on my system > > ? > > So I take it the patch I sent out didn't work for you? Can you tell me > what machine/DT you are using? I've replied to the patch: Based on v5.9-rc5, before the patch: [ 0.652887] cpuidle: using governor menu [ 12.349476] No ATAGs? After the patch: [ 0.650460] cpuidle: using governor menu [ 12.262101] No ATAGs? I'm using an AM57xx EVM, whose DT is not upstream, but it's essentially a am57xx-beagle-x15-revb1.dts (it includes that DTS) with a few additional nodes for GPIO keys, LCD panel, backlight and touchscreen. -- Regards, Laurent Pinchart