From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nishanth Menon Subject: Re: [PATCH] OMAP3: PM: Fix for Silicon bug on Context Restore on OMAP3430 Date: Tue, 6 Oct 2009 06:50:28 -0500 Message-ID: <4ACB2F04.2090608@ti.com> References: <1254741761-31546-1-git-send-email-y> <87ljjpzs9p.fsf@deeprootsystems.com> <4ACA2C83.9080400@ti.com> <5A47E75E594F054BAF48C5E4FC4B92AB030A3321EF@dbde02.ent.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from comal.ext.ti.com ([198.47.26.152]:60318 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932138AbZJFLvG (ORCPT ); Tue, 6 Oct 2009 07:51:06 -0400 In-Reply-To: <5A47E75E594F054BAF48C5E4FC4B92AB030A3321EF@dbde02.ent.ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Gopinath, Thara" Cc: Kevin Hilman , "linux-omap@vger.kernel.org" , "Gulati, Shweta" Gopinath, Thara had written, on 10/06/2009 01:59 AM, the following: > The problem here is not with the restore. If MPU reads the PADCONF_SAVEDONE bit very close > to the end of context save sequence for the pad conf registers, the last context is not > saved to the scratchpad memory. This is a h/w bug. The workaround proposed is to delay the > MPU access of SAVEDONE bit until the last context has been saved. 300 us delay is the current > safe delay proposed by TI. I believe investigations are going on to whether this delay can be > optimized. Also only the last context (ETK_D14) has the risk of not getting saved. So, if I were to save specifically the ETK14 and restore it explicitly, I could in theory work around this issue. > > We could add a defconfig option for this workaround and enable it on need basis till TI > comes out with proper optimized workaround sequence. we could probably hope to see a final patch then I believe? Regards, Nishanth Menon