Re: [rfc] i810_audio: offset LVI from CIV to avoid stalled start

[Thomas Voegtle]

On Wed, 19 Jan 2005, Herbert Xu wrote:

> On Tue, Jan 18, 2005 at 01:07:47PM -0500, John W. Linville wrote:
> > 
> > No, that does not fix it. :-(  In fact, it doesn't seem to alter the
> > problem at all...
> 
> OK.  In that case I agree with your patch.  The overruns that I
> attributed to it were probably caused by other bugs that's been
> fixed since.
> 
> Cheers,
> 


Here is the same patch against 2.6.11-rc1-bk6. Works for me.


--- linux-2.6.11-rc1-bk6/sound/oss/i810_audio.c.old	2005-01-19 09:47:20.438345600 +0100
+++ linux-2.6.11-rc1-bk6/sound/oss/i810_audio.c	2005-01-19 09:48:43.618700264 +0100
@@ -1196,10 +1196,20 @@
 	if (count < fragsize)
 		return;
 
+	/* 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, things will operate properly
+	 */
 	if (!dmabuf->enable && dmabuf->ready) {
 		if (!(dmabuf->trigger & trigger))
 			return;
 
+		CIV_TO_LVI(state->card, port, 1);
+
 		start(state);
 		while (!(I810_IOREADB(state->card, port + OFF_CR) & ((1<<4) | (1<<2))))
 			;






-- 
 Thomas Vögtle    email: thomas@xxxxxxxxxxxxxxx
 ----- http://www.voegtle-clan.de/thomas ------
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