From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: Re: [PATCH] OMAP: DSS2: DSI: Introduce sync_vc functions Date: Thu, 24 Mar 2011 10:38:31 +0200 Message-ID: <1300955911.2806.38.camel@deskari> References: <1300874374-23112-1-git-send-email-archit@ti.com> <1300952882.2806.29.camel@deskari> <4D8B02A1.9090907@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:41838 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933750Ab1CXIif (ORCPT ); Thu, 24 Mar 2011 04:38:35 -0400 Received: from dlep35.itg.ti.com ([157.170.170.118]) by arroyo.ext.ti.com (8.13.7/8.13.7) with ESMTP id p2O8cYvM006559 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 24 Mar 2011 03:38:34 -0500 Received: from dlep26.itg.ti.com (localhost [127.0.0.1]) by dlep35.itg.ti.com (8.13.7/8.13.7) with ESMTP id p2O8cYZY020275 for ; Thu, 24 Mar 2011 03:38:34 -0500 (CDT) Received: from dlee74.ent.ti.com (localhost [127.0.0.1]) by dlep26.itg.ti.com (8.13.8/8.13.8) with ESMTP id p2O8cYH7017633 for ; Thu, 24 Mar 2011 03:38:34 -0500 (CDT) In-Reply-To: <4D8B02A1.9090907@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Taneja, Archit" Cc: "linux-omap@vger.kernel.org" On Thu, 2011-03-24 at 03:36 -0500, Taneja, Archit wrote: > Hi, > > On Thursday 24 March 2011 01:18 PM, Valkeinen, Tomi wrote: > > So how to solve that... > > > > Two ways come to my mind: > > - Track sent BTAs in dsi.c. Every time we send a packet, reset the > > counter. Every time we send a BTA, increase the counter. Thus at frame > > update we would know if we need to send an extra BTA. > > > > - Always reset the BTA "status" from the panel at the beginning of frame > > transfer. This could be done by sending a null packet. > > > > The second one is probably simpler and more failsafe as there's no state > > stored. The first one (as well as the current system) would go wrong if > > something strange happens, like the panel resets. However, the second > > one introduces some overhead, as we need to send a null packet and two > > BTAs (versus one BTA) for every frame. It's probably negligible, though. > > Okay. I agree the second one is a better option. I have a couple of > queries though: > -The second BTA should be sent only after we get the Ack for the first > one, i.e, we need to use bta_sync() for the first BTA, right? True. > -We shouldn't send null packets and the 2 BTAs at all if we aren't using > Automatic TE mode, is this correct? If by automatic TE mode you mean the DSI TEE trigger, then yes. There's currently check for the dsi.te_enabled in dsi_update_screen_dispc() for that. > -Whose job should it be to send the null packet and the 2 BTAs, the dsi > driver or the panel driver? I'd say the dsi driver. It currently sends the one BTA in dsi_update_screen_dispc(). Adding one null packet and a BTA there should be quite simple. Tomi