Re: [PATCH] ALSA: hda: fix SND_INTEL_DSP_CONFIG dependency

[Takashi Iwai <tiwai@suse.de>]

On Mon, 04 Jan 2021 16:00:05 +0100,
Jaroslav Kysela wrote:
> 
> Dne 03. 01. 21 v 14:52 Arnd Bergmann napsal(a):
> > From: Arnd Bergmann <arnd@arndb.de>
> > 
> > The sof-pci-dev driver fails to link when built into the kernel
> > and CONFIG_SND_INTEL_DSP_CONFIG is set to =m:
> > 
> > arm-linux-gnueabi-ld: sound/soc/sof/sof-pci-dev.o: in function `sof_pci_probe':
> > sof-pci-dev.c:(.text+0x1c): undefined reference to `snd_intel_dsp_driver_probe'
> > 
> > All other drivers using this interface already use a 'select
> > SND_INTEL_DSP_CONFIG' statement to force the it to be present, so it
> > seems reasonable to do the same here.
> > 
> > The stub implementation in the header makes the problem harder to find,
> > as it avoids the link error when SND_INTEL_DSP_CONFIG is completely
> > disabled, without any obvious upsides. Remove these stubs to make it
> > clearer that the driver is in fact needed here.
> > 
> > Fixes: 82d9d54a6c0e ("ALSA: hda: add Intel DSP configuration / probe code")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> >  include/sound/intel-dsp-config.h | 17 -----------------
> >  sound/soc/sof/Kconfig            |  2 ++
> >  2 files changed, 2 insertions(+), 17 deletions(-)
> > 
> > diff --git a/include/sound/intel-dsp-config.h b/include/sound/intel-dsp-config.h
> > index d4609077c258..94667e870029 100644
> > --- a/include/sound/intel-dsp-config.h
> > +++ b/include/sound/intel-dsp-config.h
> > @@ -18,24 +18,7 @@ enum {
> >  	SND_INTEL_DSP_DRIVER_LAST = SND_INTEL_DSP_DRIVER_SOF
> >  };
> >  
> > -#if IS_ENABLED(CONFIG_SND_INTEL_DSP_CONFIG)
> 
> The SOF drivers selects the DSP config code only when required (for specific
> platforms - see sound/soc/sof/intel/Kconfig).
> 
> It seems that the above if should be modified as:
> 
> #if IS_BUILDIN(CONFIG_SND_INTEL_DSP_CONFIG) || (defined(MODULE) &&
> IS_MODULE(CONFIG_SND_INTEL_DSP_CONFIG))
> 
> So the buildin drivers which do not require the DSP config probe can be
> compiled without this dependency.

As I wrote in another post, a part of the problem is that SOF PCI and
ACPI drivers call snd_intel_dsp_driver_probe() unconditionally, even
if no Intel driver is bound.  So even if changing like the above (or
better to use IS_REACHABLE() macro) works around the issue, the call
pattern needs to be reconsidered.


thanks,

Takashi