From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: Re: DSS2 Query: Use of FIFO preload values Date: Tue, 09 Nov 2010 12:01:10 +0200 Message-ID: <1289296870.3297.136.camel@tubuntu> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.nokia.com ([147.243.128.24]:23214 "EHLO mgw-da01.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753569Ab0KIJ7r (ORCPT ); Tue, 9 Nov 2010 04:59:47 -0500 In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "ext Taneja, Archit" Cc: "linux-omap@vger.kernel.org" On Tue, 2010-11-09 at 05:20 +0100, ext Taneja, Archit wrote: > Hi, > > I was going through the DSS2 code and was unable to find a place > where we set the 11th bit in DISPC_GFX_ATTRIBUTES or the 19th bit > in DISPC_VIDn_ATTRIBUTES. > > Setting these bits ensures that the DISPC FIFO's fill up to the > high threshold value specified by us instead of the preload values. > > Is this done on purpose or it got missed out? A bit both. The TRM is quite unclear about fifo threshold and preload configuration, and I've never understood how to configure them for different interfaces. The current setup is mostly configured in such a way that things seem to work =). And if I recall right, even if the bits say that preload values are used, changing the threshold values still broke things. So, as I said, I never quite understood how they work. Tomi