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 87C25E92FF4 for ; Fri, 6 Oct 2023 08:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230483AbjJFIDN (ORCPT ); Fri, 6 Oct 2023 04:03:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230361AbjJFIDJ (ORCPT ); Fri, 6 Oct 2023 04:03:09 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2DBF3CA; Fri, 6 Oct 2023 01:03:08 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0EE3C433CA; Fri, 6 Oct 2023 08:03:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696579387; bh=PcmAvvx88HZXcDnWhvV/6PWlJS0yccpOIGqXi/UObtc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QlT8hPd7Un24UWMVDcvz/rzgyq3xzJU79JDYaLcghW+IT37t/3kDdeo2YShv/hJaS 6NJsNF1WVUt3a3QGCbhoXIdelm2HFTy5NZwG6ARP5IP+s9D59p2JZPcF3HeCF4s8cg SC/rJYyM5rOg9I3qLVhb4DxCvaOvHWTohzi8LvR8TC4zJY/uzbPHsvq+POUYNZsp0N 7/u38AyfeIViBjZW1QNZRauTlfam9zpt1y792gfv6uhDJ7CZkhXCEo705xUXqpK0Wh UA5HNW7eRATtjyb6kmFw9km87PV1blpPjoCYJUernMAXiKtwP42l3QQ9U8Ky/eoLTT Rt/MibdrBTyfA== Received: from johan by xi.lan with local (Exim 4.96) (envelope-from ) id 1qofnx-0004Aw-2b; Fri, 06 Oct 2023 10:03:25 +0200 Date: Fri, 6 Oct 2023 10:03:25 +0200 From: Johan Hovold To: Tony Lindgren Cc: Andy Shevchenko , Greg Kroah-Hartman , Jiri Slaby , Dhruva Gole , Ilpo =?utf-8?B?SsOkcnZpbmVu?= , John Ogness , Sebastian Andrzej Siewior , Vignesh Raghavendra , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Maximilian Luz Subject: Re: [PATCH] serial: core: Fix checks for tx runtime PM state Message-ID: References: <20231005075644.25936-1-tony@atomide.com> <20231006072738.GI34982@atomide.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231006072738.GI34982@atomide.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 06, 2023 at 10:27:38AM +0300, Tony Lindgren wrote: > * Andy Shevchenko [231005 12:01]: > > On Thu, Oct 05, 2023 at 10:56:42AM +0300, Tony Lindgren wrote: > > > The serdev device and the serial core controller devices are siblings of > > > the serial port hardware device. The runtime PM usage count from serdev > > > > I'm a bit lost in terminology here. > > AFAIU there are: > > 1) children of the serial physical device; > > 2) siblings (to each other). > > > > But may be I mistakenly deciphered the diagram from the previous discussion. > > You're right, so how about: > > The serdev device and the serial core controller devices are children of > the serial port hardware device. The runtime PM usage count from serdev > device does not propagate to the serial core device siblings, it only > propagates to the parent. That's still not accurate: - the serdev device is not a child (but a grandchild) of the serial controller - the new serial port devices are not "siblings" (but descendants) of the serial controller - the serdev controller ignores the power state of its children so that bit is also incorrect You just want to describe the fact that the serdev controller runtime PM state is currently not propagated to your new "devices" that are descendants to the serial controller. I'm still not sure why it was implemented this way, or if it is even correct, but this seems to be the state of things. Johan