From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:56862 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966977AbeCSQ06 (ORCPT ); Mon, 19 Mar 2018 12:26:58 -0400 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT To: Boris Brezillon , Eric Anholt From: Stephen Boyd In-Reply-To: <87vadz9ana.fsf@anholt.net> Cc: Florian Fainelli , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com, Stefan Wahren , Lee Jones , linux-rpi-kernel@lists.infradead.org, Mike Turquette , Stephen Boyd , linux-clk@vger.kernel.org, stable@vger.kernel.org References: <20180208134338.24590-1-boris.brezillon@bootlin.com> <20180208134338.24590-4-boris.brezillon@bootlin.com> <87mv0j5wzz.fsf@anholt.net> <20180208185619.667a4daf@bbrezillon> <87vaf6v77r.fsf@anholt.net> <20180212102752.21e22328@bbrezillon> <152088968272.205167.14856461616755294568@swboyd.mtv.corp.google.com> <87vadz9ana.fsf@anholt.net> Message-ID: <152147681675.242365.12138371754723836816@swboyd.mtv.corp.google.com> Subject: Re: [PATCH 4/4] clk: bcm2835: Make sure the PLL is gated before changing its rate Date: Mon, 19 Mar 2018 09:26:56 -0700 Sender: stable-owner@vger.kernel.org List-ID: Quoting Eric Anholt (2018-03-13 09:56:57) > Stephen Boyd writes: > > > > What exactly is going on here? It sounds like the framework isn't aware > > of the 'on/off' boot state of certain clks (a known problem) and that's > > causing some sort of problem when changing rates? This usually happens > > with PLLs that are enabled at boot time and can't support their rate > > changing when they're enabled. We really should start reading on/off > > state and "hand off" that enabled state to something in the framework so > > we at least know if a clk is enabled or not out of boot. There was some > > work on clk handoff done a while ago by Mike that never landed which may > > be useful to finish this off. Maybe we can pass that enabled state off > > to the clk we always create for a clk_hw structure at registration time > > and then have clk_disable_unused operate on that clk pointer at late > > init. > > Yes, the usual problem of clk not handling boot-time clock state well. > > That said, it's patch 1 that's critical for fixing many of our users, > and we need that in as soon as possible. #2 is also reviewed and ready. Got it. I'll pick up the first two then. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 To: Boris Brezillon , Eric Anholt From: Stephen Boyd In-Reply-To: <87vadz9ana.fsf@anholt.net> Cc: Florian Fainelli , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com, Stefan Wahren , Lee Jones , linux-rpi-kernel@lists.infradead.org, Mike Turquette , Stephen Boyd , linux-clk@vger.kernel.org, stable@vger.kernel.org References: <20180208134338.24590-1-boris.brezillon@bootlin.com> <20180208134338.24590-4-boris.brezillon@bootlin.com> <87mv0j5wzz.fsf@anholt.net> <20180208185619.667a4daf@bbrezillon> <87vaf6v77r.fsf@anholt.net> <20180212102752.21e22328@bbrezillon> <152088968272.205167.14856461616755294568@swboyd.mtv.corp.google.com> <87vadz9ana.fsf@anholt.net> Message-ID: <152147681675.242365.12138371754723836816@swboyd.mtv.corp.google.com> Subject: Re: [PATCH 4/4] clk: bcm2835: Make sure the PLL is gated before changing its rate Date: Mon, 19 Mar 2018 09:26:56 -0700 List-ID: Quoting Eric Anholt (2018-03-13 09:56:57) > Stephen Boyd writes: > > > > What exactly is going on here? It sounds like the framework isn't aware > > of the 'on/off' boot state of certain clks (a known problem) and that's > > causing some sort of problem when changing rates? This usually happens > > with PLLs that are enabled at boot time and can't support their rate > > changing when they're enabled. We really should start reading on/off > > state and "hand off" that enabled state to something in the framework so > > we at least know if a clk is enabled or not out of boot. There was some > > work on clk handoff done a while ago by Mike that never landed which may > > be useful to finish this off. Maybe we can pass that enabled state off > > to the clk we always create for a clk_hw structure at registration time > > and then have clk_disable_unused operate on that clk pointer at late > > init. > = > Yes, the usual problem of clk not handling boot-time clock state well. > = > That said, it's patch 1 that's critical for fixing many of our users, > and we need that in as soon as possible. #2 is also reviewed and ready. Got it. I'll pick up the first two then.