From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424641AbcFMPYX (ORCPT ); Mon, 13 Jun 2016 11:24:23 -0400 Received: from down.free-electrons.com ([37.187.137.238]:36256 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1423728AbcFMPYV (ORCPT ); Mon, 13 Jun 2016 11:24:21 -0400 Date: Mon, 13 Jun 2016 17:24:09 +0200 From: Alexandre Belloni To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, Nicolas Ferre , Boris Brezillon , Stephen Boyd , linux-kernel@vger.kernel.org, Cyrille Pitchen , Jean-Christophe Plagniol-Villard , linux-clk@vger.kernel.org Subject: Re: [PATCH 01/48] clk: at91: replace usleep() by udelay() calls Message-ID: <20160613152409.GD3240@piout.net> References: <1465596231-21766-1-git-send-email-alexandre.belloni@free-electrons.com> <1465596231-21766-2-git-send-email-alexandre.belloni@free-electrons.com> <11395561.bQatt85IOg@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <11395561.bQatt85IOg@wuerfel> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/06/2016 at 00:30:36 +0200, Arnd Bergmann wrote : > On Saturday, June 11, 2016 12:03:04 AM CEST Alexandre Belloni wrote: > > From: Cyrille Pitchen > > > > Fix the main and slow clock .prepare() implementations which used to call > > usleep() when the scheduler wasn't ready yet. > > > > Does this have to be called that early? It seems wasteful to always > call udelay() here, when these are functions that are normally > allowed to sleep. > So I've tested it and something like that would work: if (system_state < SYSTEM_RUNNING) udelay(osc->startup_usec); else usleep_range(osc->startup_usec, osc->startup_usec + 1); But I'm afraid it would be the first driver to actually do something like that (however, it is already the only driver trying to sleep). -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com