From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: Suspend broken on 3.3? Date: Mon, 09 Apr 2012 07:27:22 -0700 Message-ID: <87zkalc75h.fsf@ti.com> References: <87iphdeyaf.fsf@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from na3sys009aog115.obsmtp.com ([74.125.149.238]:37691 "EHLO na3sys009aog115.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755553Ab2DIO1T (ORCPT ); Mon, 9 Apr 2012 10:27:19 -0400 Received: by pbcwz17 with SMTP id wz17so5165852pbc.13 for ; Mon, 09 Apr 2012 07:27:18 -0700 (PDT) In-Reply-To: (Govindraj Raja's message of "Mon, 9 Apr 2012 16:57:23 +0530") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Raja, Govindraj" Cc: Paul Walmsley , Joe Woodward , linux-omap@vger.kernel.org, Felipe Balbi , neilb@suse.de "Raja, Govindraj" writes: [...] > So incase of uart wakeups are disabled and uart tx/rx is requested > can we prevent MPU from low power state. I think that would be a mistake. The main point of disabling UART wakeups is to save power by preventing unwanted wakups on UARTs that don't need/want them. If we then leave MPU enabled because UART wakeups are disabled, that would defeat the power-saving goals of disabling wakeups in the first place. Presumably, if a user disables UART wakeups, it means either 1) that UART is not used or 2) performance is not critical. IMO, we simply need to ensure that the defaults are correct. When UARTs are initialized/enabled wakeups should be enabled by default. The user can then override this if desired, and will obviously see a performance impact. But that's what happens with wakeups disabled. Kevin