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 6B206E92FF8 for ; Fri, 6 Oct 2023 08:37:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231180AbjJFIhQ (ORCPT ); Fri, 6 Oct 2023 04:37:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231136AbjJFIhQ (ORCPT ); Fri, 6 Oct 2023 04:37:16 -0400 Received: from muru.com (muru.com [72.249.23.125]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E3F0295; Fri, 6 Oct 2023 01:37:14 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 13D5F80E0; Fri, 6 Oct 2023 08:37:14 +0000 (UTC) Date: Fri, 6 Oct 2023 11:37:12 +0300 From: Tony Lindgren To: Johan Hovold 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: <20231006083712.GJ34982@atomide.com> 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: Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org * Johan Hovold [231006 08:03]: > 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. OK so let's just use: The serdev controller runtime PM state is not currently propagated to the serial core controller port device. The runtime PM usage count only propagates to the parent device. > 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. Care to clarify a bit which parts are unclear? The hierarchy of port devices, making serial core manage runtime PM in a generic way, or flushing tx? Regards, Tony