From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262612AbVAQSpb (ORCPT ); Mon, 17 Jan 2005 13:45:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262593AbVAQSna (ORCPT ); Mon, 17 Jan 2005 13:43:30 -0500 Received: from ra.tuxdriver.com ([24.172.12.4]:29453 "EHLO ra.tuxdriver.com") by vger.kernel.org with ESMTP id S262466AbVAQShN (ORCPT ); Mon, 17 Jan 2005 13:37:13 -0500 Date: Mon, 17 Jan 2005 13:37:08 -0500 From: "John W. Linville" To: linux-kernel@vger.kernel.org Cc: herbert@gondor.apana.org.au, jgarzik@pobox.com Subject: [rfc] i810_audio: offset LVI from CIV to avoid stalled start Message-ID: <20050117183708.GD4348@tuxdriver.com> Mail-Followup-To: linux-kernel@vger.kernel.org, herbert@gondor.apana.org.au, jgarzik@pobox.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "Some" OSS applications have trouble with later versions of the i810_audio driver. Wolfenstein Enemy Territory from idSoftware is one such application. I did a little legwork in BK and tracked-down the exact change which caused the break. The changelog comments are dismissive to the original code. However, I find that recreating a patch equivalent to what was removed restores sound to the game. Anyone have any suggestions for a patch that a) works; and, b) accounts for the concerns expressed in the changelog? John P.S. Here is the problematic patch: (DO NOT TRY TO APPLY THIS) # This is a BitKeeper generated diff -Nru style patch. # # ChangeSet # 2004/05/11 03:51:54-04:00 herbert@gondor.apana.org.au # [sound i810] remove bogus CIV_TO_LVI # # This patch removes a pair of bogus LVI assignments. The explanation in # the comment is wrong because the value of PCIB tells the hardware that # the DMA buffer can be processed even if LVI == CIV. # # Setting LVI to CIV + 1 causes overruns when with short writes # (something that vmware is very fond of). # # drivers/sound/i810_audio.c # 2004/05/11 03:51:52-04:00 herbert@gondor.apana.org.au +0 -10 # [sound i810] remove bogus CIV_TO_LVI # # This patch removes a pair of bogus LVI assignments. The explanation in # the comment is wrong because the value of PCIB tells the hardware that # the DMA buffer can be processed even if LVI == CIV. # # Setting LVI to CIV + 1 causes overruns when with short writes # (something that vmware is very fond of). # diff -Nru a/drivers/sound/i810_audio.c b/drivers/sound/i810_audio.c --- a/drivers/sound/i810_audio.c 2005-01-14 16:20:27 -05:00 +++ b/drivers/sound/i810_audio.c 2005-01-14 16:20:27 -05:00 @@ -1079,25 +1079,15 @@ else port += dmabuf->write_channel->port; - /* if we are currently stopped, then our CIV is actually set to our - * *last* sg segment and we are ready to wrap to the next. However, - * if we set our LVI to the last sg segment, then it won't wrap to - * the next sg segment, it won't even get a start. So, instead, when - * we are stopped, we set both the LVI value and also we increment - * the CIV value to the next sg segment to be played so that when - * we call start_{dac,adc}, things will operate properly - */ if (!dmabuf->enable && dmabuf->ready) { if(rec && dmabuf->count < dmabuf->dmasize && (dmabuf->trigger & PCM_ENABLE_INPUT)) { - CIV_TO_LVI(port, 1); __start_adc(state); while( !(inb(port + OFF_CR) & ((1<<4) | (1<<2))) ) ; } else if (!rec && dmabuf->count && (dmabuf->trigger & PCM_ENABLE_OUTPUT)) { - CIV_TO_LVI(port, 1); __start_dac(state); while( !(inb(port + OFF_CR) & ((1<<4) | (1<<2))) ) ; } -- John W. Linville linville@tuxdriver.com