Am Montag, 4. Februar 2008 15:47:08 schrieb Clemens Ladisch:
> Oliver Neukum wrote:
> > Am Montag, 4. Februar 2008 09:58:19 schrieb Clemens Ladisch:
> >> Oliver Neukum wrote:
> >> > this patch implements autosuspend for USB audio devices.
> >>
> >> The Creative Audigy 2 NX mutes itself when being suspended but doesn't
> >> unmute when resuming. (Apparently, this self-powered device treats
> >> supend the same as disconnection.)
> >
> > It must be added to the USB quirk list. Please provide vendor:product id.
> >
> >> The Roland SC-8820 resets itself when being resumed and loses all
> >
> > A quirk is needed, too.
>
> /* Creative SB Audigy 2 NX */
> USB_DEVICE(0x041e, 0x3020)
> /* Roland SC-8820 */
> USB_DEVICE(0x0582, 0x0007)
> /* Edirol SD-20 */
> USB_DEVICE(0x0582, 0x0027)
>
> I fear there are many other devices with similar problems.
Yes, so do I. This driver will need reset_resume().
> >> parameter settings. Furthermore, it should be possible to use this
> >> device with its external input even when the computer isn't accessing
> >> it.
> >
> > How could the device be used without the computer? Please explain.
>
> It's a MIDI synthesizer with an external MIDI input. It's possible to
> connect a MIDI keyboard directly and to use the computer just for power
> and/or for setting parameters before playing.
Does this fail while the device is suspended? Do we care? If you want
to use your computer as a power source, don't enable autosuspend.
> >> The Edirol UA-1A resumes OK (but it doesn't have any internal state).
> >
> > Not even volume? Mute/unmute?
>
> No.
So everything is lost?
> >> Your patch doesn't touch usbmidi.c -- USB MIDI devices are suspended
> >> even when they're being used.
> >
> > Yes, I noticed. I thought midi is a separate driver. Is there documentation
> > on the midi API?
>
> Documentation/DocBook/writing-an-alsa-driver, section
> "RawMIDI Interface".
>
> Just use the *_open/*_close and *_disconnect callbacks.
Thanks.
Regards
Oliver
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