Re: Re: CMI8738-MC6 surround40 plugin on 4 SP systems]

[Takashi Iwai <tiwai@suse.de>]

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At Fri, 31 Oct 2003 12:39:18 -0500,
Marcel wrote:
> 
> * Takashi Iwai (tiwai@suse.de) wrote:
> > At Thu, 30 Oct 2003 12:42:39 -0500,
> > Marcel wrote:
> > > 
> > > 
> > > I've been trying to finetune my cmipci for several weeks now.   And this is
> > > the best way I've been able to get transparent operation with various audio
> > > material: stereo, mono, 4.0, 5.1.  The main problem being no surround sound
> > > iif "Exchange DAC" setting was not set, and sound on the rear speakers only
> > > if it was.
> > 
> > ah, this might be true.
> > does it happen both on 4.0 and 5.1 outputs?
> > i don't remember that it's necessary for 5.1 at the last time i
> > tested.
> 
> With surround40 plugin, 4 speakers, yes it's needed for both 4.0 and 5.1
> material.  Applications such as mplayer or xine will remix 5.1 material to
> 4 channels.  For 6 speakers systems, I really don't know.

could you try surround51 and check whether it somehow works?

> > perhaps we should simply remove this control from user and handle
> > internally for the MC6 chip.
> > 
> 
> I agree.  Its usage is confusing and may results in improper operation

how about the attached patch?


Takashi

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Index: alsa-kernel/pci/cmipci.c
===================================================================
RCS file: /suse/tiwai/cvs/alsa/alsa-kernel/pci/cmipci.c,v
retrieving revision 1.57
diff -u -r1.57 cmipci.c
--- alsa-kernel/pci/cmipci.c	28 Oct 2003 11:25:31 -0000	1.57
+++ alsa-kernel/pci/cmipci.c	4 Nov 2003 16:24:39 -0000
@@ -728,9 +728,11 @@
 		if (channels > 4) {
 			snd_cmipci_clear_bit(cm, CM_REG_CHFORMAT, CM_CHB3D);
 			snd_cmipci_set_bit(cm, CM_REG_CHFORMAT, CM_CHB3D5C);
+			snd_cmipci_clear_bit(cm, CM_REG_MISC_CTRL, CM_XCHGDAC);
 		} else {
 			snd_cmipci_clear_bit(cm, CM_REG_CHFORMAT, CM_CHB3D5C);
 			snd_cmipci_set_bit(cm, CM_REG_CHFORMAT, CM_CHB3D);
+			snd_cmipci_set_bit(cm, CM_REG_MISC_CTRL, CM_XCHGDAC);
 		}
 		if (channels == 6) {
 			snd_cmipci_set_bit(cm, CM_REG_LEGACY_CTRL, CM_CHB3D6C);
@@ -749,6 +751,7 @@
 			snd_cmipci_clear_bit(cm, CM_REG_CHFORMAT, CM_CHB3D5C);
 			snd_cmipci_clear_bit(cm, CM_REG_LEGACY_CTRL, CM_CHB3D6C);
 			snd_cmipci_clear_bit(cm, CM_REG_MISC_CTRL, CM_ENCENTER);
+			snd_cmipci_clear_bit(cm, CM_REG_MISC_CTRL, CM_XCHGDAC);
 			spin_unlock_irqrestore(&cm->reg_lock, flags);
 		}
 	}
@@ -2671,11 +2674,14 @@
 
 /* both for CM8338/8738 */
 static snd_kcontrol_new_t snd_cmipci_mixer_switches[] __devinitdata = {
-	DEFINE_MIXER_SWITCH("Exchange DAC", exchange_dac),
 	DEFINE_MIXER_SWITCH("Four Channel Mode", fourch),
 	DEFINE_MIXER_SWITCH("Line-In As Rear", line_rear),
 };
 
+/* for non-multichannel chips */
+static snd_kcontrol_new_t snd_cmipci_nomulti_switch __devinitdata =
+DEFINE_MIXER_SWITCH("Exchange DAC", exchange_dac);
+
 /* only for CM8738 */
 static snd_kcontrol_new_t snd_cmipci_8738_mixer_switches[] __devinitdata = {
 #if 0 /* controlled in pcm device */
@@ -2748,6 +2754,11 @@
 	sw = snd_cmipci_mixer_switches;
 	for (idx = 0; idx < num_controls(snd_cmipci_mixer_switches); idx++, sw++) {
 		err = snd_ctl_add(cm->card, snd_ctl_new1(sw, cm));
+		if (err < 0)
+			return err;
+	}
+	if (! cm->can_multi_ch) {
+		err = snd_ctl_add(cm->card, snd_ctl_new1(&snd_cmipci_nomulti_switch, cm));
 		if (err < 0)
 			return err;
 	}