[I810_AUDIO] 3/x: Remove bogus CIV_TO_LVI

From: Herbert Xu <herbert@gondor.apana.org.au>
To: Jeff Garzik <jgarzik@pobox.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [I810_AUDIO] 3/x: Remove bogus CIV_TO_LVI
Date: Sat, 22 Nov 2003 18:19:35 +1100	[thread overview]
Message-ID: <20031122071935.GA27371@gondor.apana.org.au> (raw)
In-Reply-To: <20031122071345.GA27303@gondor.apana.org.au>

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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).
-- 
Debian GNU/Linux 3.0 is out! ( http://www.debian.org/ )
Email:  Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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Index: kernel-source-2.4/drivers/sound/i810_audio.c
===================================================================
RCS file: /home/gondolin/herbert/src/CVS/debian/kernel-source-2.4/drivers/sound/i810_audio.c,v
retrieving revision 1.10
diff -u -r1.10 i810_audio.c

--- kernel-source-2.4/drivers/sound/i810_audio.c	22 Nov 2003 07:14:08 -0000	1.10
+++ kernel-source-2.4/drivers/sound/i810_audio.c	22 Nov 2003 07:16:08 -0000
@@ -1069,25 +1069,15 @@
 	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))) ) ;
 		}
