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=-0.8 required=3.0 tests=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 27E09C433DF for ; Tue, 2 Jun 2020 13:37:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F0035207D8 for ; Tue, 2 Jun 2020 13:37:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727924AbgFBNhF (ORCPT ); Tue, 2 Jun 2020 09:37:05 -0400 Received: from muru.com ([72.249.23.125]:56698 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726922AbgFBNhE (ORCPT ); Tue, 2 Jun 2020 09:37:04 -0400 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 97A0D80C5; Tue, 2 Jun 2020 13:37:53 +0000 (UTC) Date: Tue, 2 Jun 2020 06:36:59 -0700 From: Tony Lindgren To: Andy Shevchenko Cc: Johan Hovold , Peter Hurley , Greg Kroah-Hartman , Vignesh Raghavendra , "open list:SERIAL DRIVERS" , Linux OMAP Mailing List , Linux Kernel Mailing List , Andy Shevchenko , Merlijn Wajer , Pavel Machek , Sebastian Reichel , "Rafael J. Wysocki" Subject: Re: [PATCH] serial: 8250_port: Fix imprecise external abort for mctrl if inactive Message-ID: <20200602133659.GD37466@atomide.com> References: <20200602001813.30459-1-tony@atomide.com> <20200602080811.GI19480@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org * Andy Shevchenko [200602 08:33]: > On Tue, Jun 2, 2020 at 11:09 AM Johan Hovold wrote: > > On Mon, Jun 01, 2020 at 05:18:13PM -0700, Tony Lindgren wrote: > > ... > > > There's shouldn't be anything fundamental preventing you from adding the > > missing resume calls to the mctrl paths even if it may require reworking > > (and fixing) the whole RPM implementation (which would be a good thing > > of course). > > Yes, for serial core I have long standing patch series to implement > RPM (more or less?) properly. Yeah let's try after the merge window. Not sure what else to do with the fix though. We currently have 8250_port.c not really aware of the hardare state for PM runtime at least for the hang-up path. > However, OMAP is a beast which prevents us to go due to a big hack > called pm_runtime_irq_safe(). > Tony is aware of this and I think the above is somehow related to removal of it. Now that we can detach and reattach the kernel serial console, there should not be any need for pm_runtime_irq_safe() anymore :) And the UART wake-up from deeper idle states can only happen with help of external hardware like GPIO controller or pinctrl controller. And for the always-on wake-up interrupt controllers we have the Linux generic wakeirqs to wake-up serial device on events. So I think the way to procedd with pm_runtime_irq_safe() removal for serial drivers is to block serial PM runtime unless we have a wakeirq configured for omaps in devicetree. In the worst case the regression is that PM runtime for serial won't work unless properly configured. And the UART wakeup latency will be a bit longer compared to pm_runtime_irq_safe() naturally. > But I completely agree that the goal is to get better runtime PM > implementation over all. Yes agreed. Regards, Tony