Re: trident (Hoontech 4d Wave NX) dropouts with small buffersize.

[Takashi Iwai <tiwai@suse.de>]

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At Sat, 9 Oct 2004 20:41:35 +0200,
Oliver Freyd wrote:
> 
> On Fri, Oct 08, 2004 at 06:39:50PM +0200, Takashi Iwai wrote:
>  
> > Hmm, how about the bigger period & buffer sizes?  Try both periods=2
> > and other cases.
> > 
> > The trident driver handles differently when period_size =
> > buffer_size/2.  If period_size != buffer_size/2, it allocates an extra
> > voice for the interrupt source.  So, if the bug occurs only with
> > periods = 2, it narrows the buggy part.
> > 
> Hello,
> 
> I've tried that, I think your idea is right. 
> The bug occurs when period_size = buffer_size/2 , also for bigger periods
> like 2048 or 4096. Then you can hear that some buffers are repeated,
> the soundcard plays them again. If you decrease period_size (even only by 1)
> it works nicely. If you increase, you get buffer underruns (aplay detects
> them). 
> 
> So it seems you have an idea of where the bug could be :-)
> 
> If you tell me what else I could do to narrow down the problem,
> I'm happy to help you!

Ok, to be sure, please try the attached patch.
This will make the driver ignoring the check of 2 periods and always
allocatint an extra voice.


Takashi

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Index: alsa-kernel/pci/trident/trident_main.c
===================================================================
RCS file: /suse/tiwai/cvs/alsa/alsa-kernel/pci/trident/trident_main.c,v
retrieving revision 1.59
diff -u -r1.59 trident_main.c
--- alsa-kernel/pci/trident/trident_main.c	30 Jul 2004 12:44:59 -0000	1.59
+++ alsa-kernel/pci/trident/trident_main.c	11 Oct 2004 15:24:30 -0000
@@ -814,7 +814,7 @@
 
 	/* voice management */
 
-	if (params_buffer_size(hw_params) / 2 != params_period_size(hw_params)) {
+	if (1 /*params_buffer_size(hw_params) / 2 != params_period_size(hw_params)*/) {
 		if (evoice == NULL) {
 			evoice = snd_trident_alloc_voice(trident, SNDRV_TRIDENT_VOICE_TYPE_PCM, 0, 0);
 			if (evoice == NULL)