From mboxrd@z Thu Jan  1 00:00:00 1970
From: Clemens Ladisch <clemens@ladisch.de>
Subject: Re: [PATCH] ALSA: usb: Work around CM6631 sample rate
 change bug
Date: Tue, 05 Mar 2013 22:39:55 +0100
Message-ID: <5136662B.7020301@ladisch.de>
References: <20130302130403.GD4452@pvv.ntnu.no> <5131FAC1.30007@gmail.com>
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 <5134781F.4050607@ladisch.de> <20130304213311.GG4452@pvv.ntnu.no>
 <5135A4D7.2050301@ladisch.de> <20130305102203.GA20417@pvv.ntnu.no>
 <5135CA77.2000805@ladisch.de> <20130305212423.GC20417@pvv.ntnu.no>
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To: Torstein Hegge <hegge@resisty.net>
Cc: Takashi Iwai <tiwai@suse.de>, alsa-devel@alsa-project.org, Daniel Mack <zonque@gmail.com>
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Torstein Hegge wrote:
> On Tue, Mar 05, 2013 at 11:35:35AM +0100, Clemens Ladisch wrote:
>> Torstein Hegge wrote:
>>> On Tue, Mar 05, 2013 at 08:55:03AM +0100, Clemens Ladisch wrote:
>>>> From that driver's .inf file:
>>>>
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0301&MI_00
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0302&MI_00
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0304&MI_00
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0305&MI_00
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0306&MI_00
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0309&MI_00
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0310&MI_00
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0311&MI_00	;CM6610A
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0312&MI_00	;CM6620A
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0313&MI_00	;CM6630A
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0314&MI_00	;CM6631A
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0319&MI_00	;CM6631A
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_0D8C&PID_0315&MI_00	;CM6632A
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_200C&PID_1030&MI_00
>>>> %CMUACWO.DeviceDesc%=CMUACWO,USB\VID_054C&PID_06CF&MI_00
>>>
>>> I'm not quite sure how to interpret that. I guess most of those are
>>> similar devices that doesn't necessarily need this workaround?
>>
>> Those are all the IDs that the C-Media driver attaches to.  The
>> hardware is always the same; I would be surprised if the firmware
>> did not have the same bug.
>
> The ids listed covers CM6610, CM6620 and CM6631, which are distinct
> pieces of hardware, or at least they are sold as if they were.

All the same chip with different labels.  I don't know if C-Media even
bothers to fuse off the unused features in the lower models.

> It might be a fair assumption that all current C-Media UAC V2.0 devices
> have this issue.

Indeed.  In any case, re-setting the interface should not hurt *any*
compliant device.


Regards,
Clemens