From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH v2 09/18] ARM: OMAP4+: PM: Restore CPU power state to ON with clockdomain force wakeup method Date: Wed, 03 Apr 2013 13:54:41 -0700 Message-ID: <87mwtftjvy.fsf@linaro.org> References: <1364205910-32392-1-git-send-email-santosh.shilimkar@ti.com> <1364205910-32392-10-git-send-email-santosh.shilimkar@ti.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail-pb0-f41.google.com ([209.85.160.41]:42400 "EHLO mail-pb0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760979Ab3DCUyp (ORCPT ); Wed, 3 Apr 2013 16:54:45 -0400 Received: by mail-pb0-f41.google.com with SMTP id mc17so1063763pbc.14 for ; Wed, 03 Apr 2013 13:54:45 -0700 (PDT) In-Reply-To: <1364205910-32392-10-git-send-email-santosh.shilimkar@ti.com> (Santosh Shilimkar's message of "Mon, 25 Mar 2013 15:35:01 +0530") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Santosh Shilimkar Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, nm@ti.com, tony@atomide.com Santosh Shilimkar writes: > While waking up CPU from off state using clock domain force wakeup, restore > the CPU power state to ON state before putting CPU clock domain under > hardware control. Otherwise CPU wakeup might fail. The change is recommended > for all OMAP4+ devices though the PRCM weakness was observed on OMAP5 > devices first. Sounds reasonable, but can you describe the "weakness" a little more? IOW, what exactly happens if this is not done? It sounds like the CPU might immediately go back to retention, but how does that happen unless it does a WFI? Also, this sounds like a fix to me, and should probably be broken out accordingly. Kevin