Re: [PATCH 1/3] ALSA: hda: add hdac_adsp_enable module flag

[Takashi Iwai <tiwai@suse.de>]

At Thu, 30 Apr 2015 20:27:26 +0100,
Mark Brown wrote:
> 
> On Thu, Apr 30, 2015 at 11:02:19AM -0500, Pierre-Louis Bossart wrote:
> > On 4/30/15 9:52 AM, Vinod Koul wrote:
> 
> > >Some Intel HDA controllers sport a DSP. These systems can also be enabled
> > >with ASoC HDA driver as well. So add a flag in hda-core to enable/disable
> > >aDSP This flag for now is false, and should be true once the ASoC based
> > >systems mature.  The integrators/OS vendors can configure this flag based on
> > >system preference.
> 
> > This choice is contingent on the BIOS options, you can't enable the DSP if
> > the BIOS said no DSP...
> 
> Presumably this flag should be coming from the BIOS by default and this
> providing a disable only setting for test/development?

It's hard to know exactly how many models will be with DSP and how
many without...  The problem we're dealing with is that we'll have two
individual drivers supporting the very same PCI ID.  And, there is no
good mechanism to prioritize the driver load on Linux, so far.

So, this is the consequence after lengthy discussions: it's fairly
simple but effective enough.  Distros may build both drivers, but
which driver to use can be decided by this option.  The default value
of this switch should be set via a Kconfig, but it can be overridden
dynamically via either a static module option or boot option.


Takashi