Re: [PATCH v2] ALSA: x86: Select CONFIG_HDMI_LPE_AUDIO as default

[Takashi Iwai <tiwai@suse.de>]

On Mon, 20 Mar 2017 09:17:30 +0100,
Ian W MORRISON wrote:
> 
> Oops ... forgot to copy alsa-devel and Pierre-Louis.
> 
> On 20 March 2017 at 18:59, Takashi Iwai <tiwai@suse.de> wrote:
> 
> > On Mon, 20 Mar 2017 08:42:32 +0100,
> > Ian W MORRISON wrote:
> > >
> > > The upstream kernel builds for distributions such as Ubuntu which now
> > > includes binary packages for v4.11 mainline kernel release candidates are
> > > promoted as a way of testing upstream kernels to to confirm that upstream
> > > has fixed a specific issue (see https://wiki.ubuntu.com/
> > > Kernel/MainlineBuilds).
> > >
> > > Unfortunately the long awaited patch for providing HDMI audio support for
> > > Bay Trail and Cherry Trail devices does not include this support through
> > a
> > > module built by default.
> > >
> > > Through including by default of the two associated CONFIG settings
> > (SND_X86
> > > and HDMI_LPE_AUDIO), upstream kernel builds would automatically provide
> > the
> > > much desired HDMI audio support by default.
> > >
> > > This patch uses a Kconfig 'default' statement to include the driver as
> > > default.
> > >
> > > Changes in version 2: CONFIG_SND_X86 now a bool and changed default m to
> > > default y
> > >
> > > Signed-off-by: Ian W Morrison <linuxium@linuxium.com.au>
> > > ---
> > >  sound/x86/Kconfig | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/sound/x86/Kconfig b/sound/x86/Kconfig
> > > index 84c8f8fc..cac2270 100644
> > > --- a/sound/x86/Kconfig
> > > +++ b/sound/x86/Kconfig
> > > @@ -1,6 +1,7 @@
> > >  menuconfig SND_X86
> > > -       tristate "X86 sound devices"
> > > +       bool "X86 sound devices"
> > >         depends on X86
> > > +       default y
> >
> > This one is OK, but ...
> >
> > >         ---help---
> > >           X86 sound devices that don't fall under SoC or PCI categories
> > >
> > > @@ -9,6 +10,7 @@ if SND_X86
> > >  config HDMI_LPE_AUDIO
> > >         tristate "HDMI audio without HDaudio on Intel Atom platforms"
> > >         depends on DRM_I915
> > > +       default y
> >
> > ... this is wrong.  Each driver config itself should be left
> > unspecified.
> >
> > It's distributor's job to choose the right config here.
> >
> > Actually this goes back to one of my earlier points: A distributor doesn't
> have to set 'HDMI' as HDMI audio is automatically provided.

Provided by who...?

> This is just an
> extension because by setting 'HDMI_LPE_AUDIO' the missing audio support for
> BYT and CHT SoCs is then provided. Therefore, in this albeit unusual
> instance, I reason is it appropriate to set HDMI_LPE_AUDIO so that audio is
> automatically provided regardless of distribution. If a distributor didn't
> want to allow audio for BYT and CHT SoC based devices running their distro
> then they could always remove it from their distro specific config.

It's a wrong approach.  What we're discussing about is just a
configuration for a new individual driver, and the same rule should be
applied to it like others.

Check other drivers.  See whether default=y (or =m) is set to
CONFIG_E1000E, as a random example.  With your argument, it should  be
set to y or m as default, since the Ethernet functionality is already
provided by the network core.

In general, we don't set the default values to the driver configs
unless there is a VERY specific reason to do so.


Takashi