Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965644AbaGPQku (ORCPT ); Wed, 16 Jul 2014 12:40:50 -0400 Received: from www.linutronix.de ([62.245.132.108]:57987 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965609AbaGPQkH (ORCPT ); Wed, 16 Jul 2014 12:40:07 -0400 Message-ID: <53C6AAE1.7090802@linutronix.de> Date: Wed, 16 Jul 2014 18:40:01 +0200 From: Sebastian Andrzej Siewior User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.0 MIME-Version: 1.0 To: balbi@ti.com CC: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Tony Lindgren , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Greg Kroah-Hartman , mika.westerberg@linux.intel.com Subject: Re: [PATCH 4/5] tty: serial: 8250 core: add runtime pm References: <1405521903-5877-1-git-send-email-bigeasy@linutronix.de> <1405521903-5877-5-git-send-email-bigeasy@linutronix.de> <20140716151604.GG1365@saruman.home> <53C6A050.2050409@linutronix.de> <20140716160614.GI1365@saruman.home> In-Reply-To: <20140716160614.GI1365@saruman.home> X-Enigmail-Version: 1.6+git0.20140323 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/16/2014 06:06 PM, Felipe Balbi wrote: >>> well, other than in probe and other functions which need to >>> make sure clocks are on, but it seems unnecessary to >>> enable/disable in every function. >> >> What do you have in mind? Do you plan to let the uart on while >> the minicom is attached but is doing nothing? In that case, >> ->startup() and ->shutdown() should be enough. > > no the idea was to keep it on for as long as it's transferring > characters and idle it otherwise, if that can't be done easily, > then I guess your way is the only way. But maybe we have to add some additional logic here to keep it up for the transfer. I've been just (maybe over)thinking: If you send 300 bytes over DMA via 300 baud it should take 10 seconds. The PM-timeout could hit before the transfer is complete. Same thing with hw-flowcontrol where you could get stalled for a few seconds. However it doesn't seem to be a problem in current omap-serial driver. > cheers Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/