Re: [PATCH] ARM: mach-shmobile: tidyup: sound card detection order

[Simon Horman <horms@verge.net.au>]

On Tue, May 29, 2012 at 06:09:47PM -0700, Kuninori Morimoto wrote:
> 
> Hi
> 
> > Hi Simon
> > 
> > Thank you for your reply
> > 
> > > > And I'm not sure ALSA already has index specification method.
> > > > Sorry for my confusion.
> > > > My problem was deferred probe order on built-in.
> > > 
> > > I was under the impression that the index could be set for a built-in too.
> > > But poking around in /sys on an armadillo board, that seems not to be the
> > > case.
> > 
> > I guess on /sys index is depends on .id ? 
> > In mackerel case, it is
> > 
> > static struct platform_device fsi_ak4643_device = {
> > 	.name	= "asoc-simple-card",
> >         ...
> > }
> > 
> > static struct platform_device fsi_hdmi_device = {
> > 	.name	= "asoc-simple-card",
> > 	.id	= 1,
> >         ...
> > }
> > 
> > # fsi_ak4643_device didn't have .id = 0, but it is.
> > 
> > Does these appear on /sys ?
> > 
> > Now, platform_device order are
> > 
> > static struct platform_device *mackerel_devices[] __initdata = {
> > 	...
> > 	&fsi_ak4643_device,  // .id = 0
> > 	&fsi_hdmi_device,    // .id = 1
> > 	...
> > }
> > 
> > ALSA sound card list order is same as detected/probed order, not these .id order.
> > 
> > > > Current my issue is...
> > > >   normal probe of ALSA-card.0  -> requests probe deferral
> > > >   normal probe of ALSA-card.1  -> requests probe deferral
> > > >   ...
> > > >   deferred-probe of ALSA-card.1  <= order changed
> > > >   deferred-probe of ALSA-card.0  <= order changed
> > 
> > So, if this happen, ALSA-card list order become un-expected order.
> > 
> > > I'm not entirely sure it makes any sense to be relying on the
> > > order of cards being initialised. But I guess the order of
> > > initialisation is relied on in other places too.
> > 
> > It decides "1st player", "2nd player".
> > I'm expecting "fsi_ak4643" is 1st player, but...
> 
> This means if it was "built-in" case

Hi Morimoto,

thanks for the clarification. Given the circumstances I think that
your original patch is fine.