[alsa-devel] [PATCH 0/3] Allow suspend/resume with USB audio.
dgreid at chromium.org
Mon Sep 17 22:11:36 CEST 2012
Problem being addressed:
shell one$ aplay -Dhw:<usbcard> file.wav
shell two$ echo mem > /sys/power/state
After resume, aplay attempts resume, then restart, then after a timeout
gets a write error and no audio will be played until it is restarted.
During suspend/resume, if the USB port remains powered the audio device
will still be present upon resume. The interface and endpoint have to
be reconfigured however. These patches move the configuration from
hw_params to prepare causing re-configuration during resume.
Is this the right way to fix this? Or is there an easier way I am
Thanks for looking.
Dylan Reid (3):
ALSA: usb-audio: set period_bytes in substream.
ALSA: usb-audio: Don't require hw_params in endpoint.
ALSA: usb-audio: Move configuration to prepare.
sound/usb/card.h | 2 +
sound/usb/endpoint.c | 29 +++++++-----
sound/usb/endpoint.h | 5 ++-
sound/usb/pcm.c | 121 +++++++++++++++++++++++++++++++--------------------
4 files changed, 97 insertions(+), 60 deletions(-)
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