From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ilya Yanok Subject: Re: [PATCH] OMAP3: hwmod_data: add HWMOD_INIT_NO_RESET flag for dss_dispc Date: Thu, 22 Dec 2011 16:42:32 +0400 Message-ID: <4EF325B8.2090206@emcraft.com> References: <1324515653-17287-1-git-send-email-yanok@emcraft.com> <1324548785.13282.10.camel@deskari> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from ocean.emcraft.com ([213.221.7.182]:41954 "EHLO ocean.emcraft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752581Ab1LVMmD (ORCPT ); Thu, 22 Dec 2011 07:42:03 -0500 In-Reply-To: <1324548785.13282.10.camel@deskari> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tomi Valkeinen Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Archit Taneja , Paul Walmsley Hi Tomi, On 22.12.2011 14:13, Tomi Valkeinen wrote: > On Thu, 2011-12-22 at 02:00 +0100, Ilya Yanok wrote: >> Resetting DISPC when a DISPC output is enabled causes the DSS to go into >> an inconsistent state. >> >> commit b923d40dd4211c4ef7d4efa2bd81b7ca1d8744c1 >> Author: Archit Taneja >> Date: Thu Oct 6 18:04:08 2011 -0600 >> >> ARM: OMAP2PLUS: DSS: Ensure DSS works correctly if display is >> enabled in bootloader >> >> tries to deal with this problem by checking if display is enabled and >> disabling it before doing reset. >> >> But in my setup dss_dispc is resetted from omap_hwmod_setup_all function >> _before_ calling omap_dss_reset. So when dispc_disable_outputs is >> executed dispc is already reset and nothing happens. > > Hmm, why is that? You don't have the dss hwmod before dispc in the list > of hwmods? The code presumes that dss hwmod is handled first. Looking at the arch/arm/mach-omap2/omap_hwmod_3xxx_data.c I can see that dss_dispc is in the list of generic hwmods which is registered first while dss_core hwmod is in revision-specific lists which are registered later. I think this is the real root of the problem, thanks for pointing this out! > >> This patch and HWMOD_INIT_NO_RESET flags to dss_dispc hwmod thus leaving >> DISPC untouched so that omap_dss_reset can take care of it. > > omap_dss_reset() doesn't reset dispc, so this will leave dispc > un-reseted. > > The idea of the current code is to do the reset similarly on all OMAPs. > The sequence should be: > > - omap_dss_reset(), which disables dispc outputs and manually resets dss > registers. > - then the rest of the dss modules reset themselves normally, using the > softreset bit. But currently omap_dss_reset() is called the last. Regards, Ilya.