[alsa-devel] [RFC] ASoC: core: Allow DAI links to be specified by using ACPI names

Liam Girdwood liam.r.girdwood at intel.com
Thu Oct 3 18:56:06 CEST 2013

On Thu, 2013-10-03 at 20:59 +0530, Vinod Koul wrote:
> On Thu, Oct 03, 2013 at 05:22:45PM +0300, Jarkko Nikula wrote:
> > On 10/03/2013 04:37 PM, Mark Brown wrote:
> > >On Thu, Oct 03, 2013 at 03:33:56PM +0300, Jarkko Nikula wrote:
> > >
> > >>For instance, matchine drivers could specify codec in DAI link by using:
> > >>	.codec_name = "INT33CA:00",
> > >>instead of
> > >>	.codec_name = "rt5640.0-001c",
> > >>Note that ACPI name is used just an alias during bind time and core
> > >>continues to use device name. In fact, machine drivers could use either
> > >>names.
> > >This is making me wonder if we shouldn't be taking the stable names we
> > >get from ACPI as the dev_name() instead of our internal ones on ACPI
> > >systems (and possibly something similar on DT) rather than adding custom
> > >code like this.
> > This is actually somewhat confusing issue. I think it's relatively
> > easy to switch using ACPI names within ASoC core (by modifying
> > fmt_single_name or something like that).
> > 
> > Problem is that for ACPI enumerated client devices the dev_name(dev)
> > still comes from those subsystems as before. So for instance dev_
> > prints in codec driver or ASoC core keeps printing "rt5640 0-001c:"
> > as before and I personally find it a bit more confusing if internal
> > ASoC names don't match as easily with dev_ prints.
> > 
> > But yes, I agree. This alias name in DAI link is not that clear
> > either as it exists only during bind time.
> Sorry am very ignorant about ACPI, but cant resist asking why should ACPI
> allocate some internal name and then we go about figuring the bus, slave and
> codec. Wouldn't it make sense to just get "rt5640.0-001c" as device from ACPI
> and use it.

We have the situation whereby some BIOS settings can alter the I2C bus
number used by the codec. i.e. matching fail on "rt5640.0-001c" but
would succeed on "rt5640.7-001c".

Moving this to also support ACPI names would be a bonus since we would
only need to match on the static ACPI device name.


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