From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from tex.lwn.net ([70.33.254.29]:57016 "EHLO vena.lwn.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750713Ab2LPWwe (ORCPT ); Sun, 16 Dec 2012 17:52:34 -0500 Date: Sun, 16 Dec 2012 15:55:03 -0700 From: Jonathan Corbet To: Albert Wang Cc: "g.liakhovetski@gmx.de" , "linux-media@vger.kernel.org" , Libin Yang Subject: Re: [PATCH V3 15/15] [media] marvell-ccic: add 3 frame buffers support in DMA_CONTIG mode Message-ID: <20121216155503.2ce60997@lwn.net> In-Reply-To: <477F20668A386D41ADCC57781B1F70430D13C8CCE7@SC-VEXCH1.marvell.com> References: <1355565484-15791-1-git-send-email-twang13@marvell.com> <1355565484-15791-16-git-send-email-twang13@marvell.com> <20121216095601.4a086356@hpe.lwn.net> <477F20668A386D41ADCC57781B1F70430D13C8CCE7@SC-VEXCH1.marvell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: On Sun, 16 Dec 2012 14:34:31 -0800 Albert Wang wrote: > >What is the purpose of the "usebufs" field? The code maintains it in > >various places, but I don't see anywhere that actually uses that value for > >anything. > > > [Albert Wang] Two buffers mode doesn't need it. > But Three buffers mode need it indicates which conditions we need set the single buffer flag. > I used "tribufs" as the name in the previous version, but it looks it's a confused name when we merged > Two buffers mode and Three buffers mode with same code by removing #ifdef based on your comments months ago. :) > So we just changed the name with "usebufs". OK, I misread the code a bit, sorry. I do find the variable confusing still, but it clearly does play a role. I think that using three buffers by default would make sense. I don't think that increased overruns are an unbreakable ABI feature :) Feel free to add my ack to this one. Thanks, jon