[PATCH] cm6206: turn off de-emphasis in s/pdif

[PATCH] cm6206: turn off de-emphasis in s/pdif

[Eric Lammerts]

Hi,
I just bought a device with a CM6206. Thank you for the quirk that 
made it work out-of-the-box! I noticed on my DAC that the de-emphasis 
LED was on. Is this by accident? Below is a patch (based on the info 
in the CM6206+datasheet+1.7.pdf that I found somewhere) that turns it 
off.

cheers,

Eric


Index: linux-2.6.36/sound/usb/quirks.c
===================================================================
--- linux-2.6.36.orig/sound/usb/quirks.c	2010-11-16 18:55:51.000000000 -0500
+++ linux-2.6.36/sound/usb/quirks.c	2010-11-16 18:55:57.000000000 -0500
@@ -387,7 +387,7 @@
  static int snd_usb_cm6206_boot_quirk(struct usb_device *dev)
  {
  	int err, reg;
-	int val[] = {0x200c, 0x3000, 0xf800, 0x143f, 0x0000, 0x3000};
+	int val[] = {0x2004, 0x3000, 0xf800, 0x143f, 0x0000, 0x3000};

  	for (reg = 0; reg < ARRAY_SIZE(val); reg++) {
  		err = snd_usb_cm106_write_int_reg(dev, reg, val[reg]);

Re: [PATCH] cm6206: turn off de-emphasis in s/pdif

[Adrian Pardini]

On 16/11/2010, Eric Lammerts <alsa-devel@lists.lammerts.org> wrote:
>
> Hi,
> I just bought a device with a CM6206. Thank you for the quirk that
> made it work out-of-the-box! I noticed on my DAC that the de-emphasis
> LED was on. Is this by accident? Below is a patch (based on the info
> in the CM6206+datasheet+1.7.pdf that I found somewhere) that turns it
> off.
>

Hi all, I have to resubmit some patches for the same chip related to
headphone support. Will you find it useful if I added the de-emphasis
control as a mixer switch?


cheers.


-- 
Adrian.
http://ovejafm.com
http://elesquinazotango.com.ar

Re: [PATCH] cm6206: turn off de-emphasis in s/pdif

[Eric Lammerts]

On Tue, 16 Nov 2010, Adrian Pardini wrote:
> Hi all, I have to resubmit some patches for the same chip related to
> headphone support. Will you find it useful if I added the de-emphasis
> control as a mixer switch?

I don't think it would add that much value, pre-emphasis is hardly 
ever used. And if there are applications that care about it, they 
probably can handle it in software, since many drivers don't have 
such a mixer switch.

If you do make it a mixer switch, I would appreciate it if the 
default is "off" :-).

Eric

Re: [PATCH] cm6206: turn off de-emphasis in s/pdif

[Clemens Ladisch]

Eric Lammerts wrote:
> I noticed on my DAC that the de-emphasis LED was on. Is this by
> accident?

Probably.  The mechanism to set the S/PDIF status bits should be added
to the driver, but as long as we do not have that, setting this bit by
default is silly.

> Below is a patch that turns it off.

Thanks.  Please provide a Signed-off-by tag as described in
Documentation/SubmittingPatches.


Regards,
Clemens

Re: [PATCH] cm6206: turn off de-emphasis in s/pdif

[Eric Lammerts]

On Thu, 18 Nov 2010, Clemens Ladisch wrote:
> Thanks.  Please provide a Signed-off-by tag as described in
> Documentation/SubmittingPatches.


CM6206: Turn off de-emphasis channel status bit in S/PDIF output.

Signed-off-by: Eric Lammerts <eric@lammerts.org>

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index cf8bf08..3e9d870 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -387,7 +387,7 @@ static int snd_usb_cm106_boot_quirk(struct usb_device *dev)
  static int snd_usb_cm6206_boot_quirk(struct usb_device *dev)
  {
  	int err, reg;
-	int val[] = {0x200c, 0x3000, 0xf800, 0x143f, 0x0000, 0x3000};
+	int val[] = {0x2004, 0x3000, 0xf800, 0x143f, 0x0000, 0x3000};

  	for (reg = 0; reg < ARRAY_SIZE(val); reg++) {
  		err = snd_usb_cm106_write_int_reg(dev, reg, val[reg]);

Re: [PATCH] cm6206: turn off de-emphasis in s/pdif

[Takashi Iwai]

At Thu, 18 Nov 2010 10:11:11 +0100,
Clemens Ladisch wrote:
> 
> Eric Lammerts wrote:
> > I noticed on my DAC that the de-emphasis LED was on. Is this by
> > accident?
> 
> Probably.  The mechanism to set the S/PDIF status bits should be added
> to the driver, but as long as we do not have that, setting this bit by
> default is silly.

Clemens, would you implement this?

Providing the IEC958 status control must be easy, but the problem
is rather alsa-lib config...


thanks,

Takashi

Re: [PATCH] cm6206: turn off de-emphasis in s/pdif

[Clemens Ladisch]

Takashi Iwai wrote:
> Clemens Ladisch wrote:
> > Eric Lammerts wrote:
> > > I noticed on my DAC that the de-emphasis LED was on. Is this by
> > > accident?
> > 
> > Probably.  The mechanism to set the S/PDIF status bits should be added
> > to the driver, but as long as we do not have that, setting this bit by
> > default is silly.
> 
> Clemens, would you implement this?

Yes, it's on my TODO list.


Regards,
Clemens