[alsa-devel] PCM Volume on FSC V5505

[Takashi Iwai]

At Tue, 27 Nov 2007 16:19:56 +0100,
I wrote:
> 
> At Fri, 23 Nov 2007 17:45:21 +0100,
> Jan-Simon Möller wrote:
> > 
> > Hi !
> > With the patches, the sound works - well done! 
> > But I need to make sure the PCM volume is max @ 50% .
> > If its over 50% sound is clipped and ugly (overload?).
> 
> Looks like so.  Mixer apps (e.g. alsamixer) can show its dB value
> instead of percent.  Check the dB level shown there.
> 
> The patch below may fix this issue.  Give it a try.

Argh, the patch is wrong.  Use the below instead.


Takashi

diff -r 17223a4918b4 pci/hda/patch_conexant.c
--- a/pci/hda/patch_conexant.c	Tue Nov 27 15:27:17 2007 +0100
+++ b/pci/hda/patch_conexant.c	Tue Nov 27 16:50:37 2007 +0100
@@ -826,6 +826,17 @@ static int patch_cxt5045(struct hda_code
 		spec->init_verbs[0] = cxt5045_test_init_verbs;
 #endif	
 	}
+
+	/*
+	 * Fix max PCM level to 0 dB
+	 * (originall it has 0x2b steps with 0dB offset 0x14)
+	 */
+	snd_hda_override_amp_caps(codec, 0x17, HDA_INPUT,
+				  (0x14 << AC_AMPCAP_OFFSET_SHIFT) |
+				  (0x14 << AC_AMPCAP_NUM_STEPS_SHIFT) |
+				  (0x05 << AC_AMPCAP_STEP_SIZE_SHIFT) |
+				  (1 << AC_AMPCAP_MUTE_SHIFT));
+
 	return 0;
 }