Takashi Iwai wrote:
The commit [88a8516a: ALSA: usbaudio: implement USB autosuspend] added the support of autopm for USB MIDI output, but it didn't take the MIDI input into account.
This patch adds the following for fixing the autopm:
- Manage the URB start at the first MIDI input stream open, instead of the time of instance creation
- Move autopm code to the common substream_open()
- Make snd_usbmidi_input_start/_stop() more robust and add the running state check
Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de ... +static int substream_open(struct snd_rawmidi_substream *substream, int dir,
int open){ struct snd_usb_midi* umidi = substream->rmidi->private_data; struct snd_kcontrol *ctl;
int err;
down_read(&umidi->disc_rwsem); if (umidi->disconnected) { up_read(&umidi->disc_rwsem);
return open ? -ENODEV : 0;}
mutex_lock(&umidi->mutex); if (open) {
if (!umidi->opened[0] && !umidi->opened[1]) {err = usb_autopm_get_interface(umidi->iface);umidi->autopm_reference = err >= 0;if (err < 0 && err != -EACCES) {up_read(&umidi->disc_rwsem);return -EIO;
umidi->mutex is still held here.
Otherwise, for both patches: Reviewd-by: Clemens Ladisch clemens@ladisch.de Tested-by: Clemens Ladisch clemens@ladisch.de
Regards, Clemens