[alsa-devel] [PATCH 0/3] ALSA: snd-usb: Some small fixes to make Playback Design products work
tiwai at suse.de
Mon Mar 18 10:07:39 CET 2013
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.
> 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(-)
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