On Tue, 09 Jul 2019 18:24:30 +0200,
Geoffrey D. Bennett wrote:
>
> On Tue, Jul 09, 2019 at 03:57:28PM +0200, Takashi Iwai wrote:
> [...]
> > > But I tested suspending while the delayed work
> > > was waiting and it seemed like the delayed work was cancelled
> > > anyway. Probably better to do a flush on suspend though;
> >
> > The flush would block, hence it wastes lots of time at suspend.
> > Ideally the suspend should be performed immediately.
> >
> > > should this
> > > be done through a hook like:
> > >
> > > diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
> > > index 2444737a14b2..1572a89267c6 100644
> > > --- a/sound/usb/mixer.c
> > > +++ b/sound/usb/mixer.c
> > > @@ -3547,6 +3547,8 @@ static int snd_usb_mixer_activate(struct usb_mixer_interface *mixer)
> > > int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer)
> > > {
> > > snd_usb_mixer_inactivate(mixer);
> > > + if (mixer->private_suspend)
> > > + mixer->private_suspend(mixer);
> > > return 0;
> > > }
> > >
> > > diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
> > > index fa6e216a06f0..d94c688c65f7 100644
> > > --- a/sound/usb/mixer.h
> > > +++ b/sound/usb/mixer.h
> > > @@ -28,6 +28,7 @@ struct usb_mixer_interface {
> > >
> > > void *private_data;
> > > void (*private_free)(struct usb_mixer_interface *private_data);
> > > + void (*private_suspend)(struct usb_mixer_interface *);
> > > };
> > >
> > > #define MAX_CHANNELS 16 /* max logical channels */
> > >
> > > ...or just keep the existing behaviour where it seems to get
> > > cancelled?
> >
> > I'm fine to add the new suspend/resume callbacks, but maybe the
> > corresponding resume would be needed.
>
> Did you mean "wouldn't be needed"?
No, it's needed because at resume you'd reschedule the work that was
canceled at suspend. It's specific.
> [...]
> > > +static int scarlett_gen2_mixer_enable;
> > > +module_param(scarlett_gen2_mixer_enable, int, 0444);
> > > +MODULE_PARM_DESC(scarlett_gen2_mixer_enable,
> > > + "Focusrite Scarlett Gen 2 Mixer Driver Enable");
> >
> > Do we need this? If disabling the quirk is really required, it should
> > be implemented rather in a generic option, instead.
>
> Actually it would be best to have it disabled by default as I have had
> two reports from people who tried this mixer driver and it broke audio
> for them.
Hm, and these have the same USB device ID?
> The failure looks like this... the first vendor-specific USB message
> sent to the interface to initialise it results in an error:
>
> e2d87480 3146602314 S Ci:1:007:0 s a1 03 0000 0005 0010 16 <
> e2d87480 3152107418 C Ci:1:007:0 -2 0
>
> My mixer driver gives up initialising, and subsequent USB messages
> fail:
>
> e2d87480 3152110424 S Ci:1:007:0 s 80 06 0304 0409 00ff 255 <
> e2d87480 3152121815 C Ci:1:007:0 -71 0
> e2d87480 3152121955 S Ci:1:007:0 s 80 06 0304 0409 0002 2 <
> e2d87480 3152131554 C Ci:1:007:0 -71 0
> e2d87480 3152133420 S Ci:1:007:0 s 80 06 0305 0409 00ff 255 <
> e2d87480 3157224469 C Ci:1:007:0 -2 0
>
> I don't see any way to distinguish between devices that do and don't
> work before sending the initialisation message. lsusb -v output is
> identical. I need someone to do a USB capture to see what the vendor
> driver does differently, but I haven't found someone who can do this
> yet.
>
> I have 9 success reports so far and 2 failure reports. I hope that by
> getting this driver out to a wider audience I can get the data I need
> to make it work in all cases and then we can remove the
> scarlett_gen2_mixer_enable quirk and have the driver always enabled.
>
> Thanks for your feedback again. The other things which I didn't
> comment on I agree with and will fix.
I guess you can use chip->setup value for the quirk-specific
configuration as a start. It's a bit hackish but the parameter is
already there for long time, hence you don't need to add any extra
stuff for that.
thanks,
Takashi
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