[alsa-devel] [PATCH - seq 1/1] ALSA seq: expose the card number of ALSA seq clients

[Takashi Iwai]

At Thu, 11 Jun 2015 23:43:53 -0400,
Adam Goode wrote:
> 
> On Mon, Jun 8, 2015 at 7:23 AM, Takashi Iwai <tiwai at suse.de> wrote:
> 
> > At Thu,  4 Jun 2015 21:04:50 -0400,
> > Adam Goode wrote:
> > >
> > > Expose the card number of seq clients. This allows interested userspace
> > > programs to discover the hardware device that backs a particular seq
> > > client. Before this change, the only way to get information about the
> > > hardware for a client was by using brittle heuristics.
> > >
> > > Signed-off-by: Adam Goode <agoode at google.com>
> >
> > The patch looks almost good.  (One coding style fix about one-line if
> > would be better, though.)
> >
> > However, if we want to have more changes, I'd prefer the protocol
> > version bump after all changes are merged.
> > Are you going to submit any further changes?
> >
> >
> > thanks,
> >
> > Takashi
> >
> 
> Hi Takashi,
> 
> I fixed up the patch in v2. It fixes the style issue and delays updating
> protocol for now.
> 
> I think there might be another useful field to expose (the hardware midi
> device number), but I'm not sure yet. It is complicated since OPL3 does
> expose a client but does not use rawmidi. Otherwise, the rawmidi device
> number would be the obvious choice. I'm pretty sure I just need the card
> number to solve my problems in Chrome, but I will have to think about it.

IMO, we need to give the interface type (rawmidi, hwdep), too.  Then
the client can open the device and query more detailed information.

> The only other interesting change to make right now would be a tstamp field
> (something like PCM), but it might be too complex for a quick fix. I do
> like the PCM timestamp mode selection, and would like to see such a thing
> in seq.

Yeah, this one would be more intrusive changes.


thanks,

Takashi