[alsa-devel] [PATCH 0/3] ALSA: snd-usb: Some small fixes to make Playback Design products work

[Takashi Iwai]

At Sun, 17 Mar 2013 20:07:23 +0800,
Daniel Mack wrote:
> 
> Thanks to Andreas, I got my hands on a Playback Design MPD-3 and hacked
> up some small hanges necessary to make it fully work with snd-usb.
> 
> The device reports 0x80000000 in the bmFormats field of two of three of
> its alternate settings, which wrongly made the driver believe it's a
> usual PCM endpoint (actually due to a fix-up fallback). However, bit 31
> of this mask in fact denotes 'raw data'.
> 
> The effect of this issue is that in addition to the first altsetting with
> a bit depth of 24, the driver exposed 8-bit and 16-bit native audio
> formats on the raw data endpoints, which do not work as expected.
> 
> Also, those devices need a 50ms delay after switching the USB interface.

Thanks, applied to for-next branch.

The remaining question is which PCM format is suitable for the raw
data.  SND_PCM_FORMAT_SPECIAL should be OK, it won't regress at least,
as no apps support this format.


Takashi

> 
> 
> Thanks,
> Daniel
> 
> 
> Daniel Mack (3):
>   ALSA: snd-usb: handle the bmFormats field as unsigned int
>   ALSA: snd-usb: handle raw data format of UAC2 devices
>   ALSA: snd-usb: add delay quirk for "Playback Design" products
> 
>  include/linux/usb/audio-v2.h |    2 ++
>  sound/usb/format.c           |   20 ++++++++++++--------
>  sound/usb/format.h           |    2 +-
>  sound/usb/pcm.c              |    7 +++++++
>  sound/usb/stream.c           |    2 +-
>  5 files changed, 23 insertions(+), 10 deletions(-)
> 
> -- 
> 1.7.10.4
>