[alsa-devel] [PATCH] cm6206: turn off de-emphasis in s/pdif
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]);
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.
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
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
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]);
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
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
participants (4)
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Adrian Pardini -
Clemens Ladisch -
Eric Lammerts -
Takashi Iwai