[alsa-devel] [PATCH v2] ALSA: x86: Select CONFIG_HDMI_LPE_AUDIO as default

[Ian W MORRISON]

On 20 March 2017 at 19:41, Takashi Iwai <tiwai at suse.de> wrote:

> 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 at 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 at 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...?
>


I suppose it is provided as a result of the architecture one runs the
primary Makefile on. With 'uname -m' returning 'x86_64' running 'make
defconfig' results in 'CONFIG_HDMI=y' being set so 'drivers/video/Makefile'
automatically makes 'drivers/video/hdmi.c' and as
'arch/x86/configs/x86_64_defconfig' includes 'CONFIG_DRM=y' and
'CONFIG_DRM_I915=y' and 'drivers/gpu/drm/i915/Makefile' makes
'intel_audio.c'.



> > 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.
>
>
I'm trying to get HDMI audio by default for BYT & CHT SoC but currently
this requires 'CONFIG_HDMI_LPE_AUDIO' set with a value of 'm'. I don't want
to argue a 'special case' or promote a 'wrong approach' but just get HDMI
audio working so is there another way to achieve this? Would adding
'CONFIG_HDMI_LPE_AUDIO=y' to 'arch/x86/configs/x86_64_defconfig' be another
mistake (assuming 'CONFIG_SND_X86' was set as per the first part of the
revised patch)? Would anyone even accept a patch
to 'arch/x86/configs/x86_64_defconfig' if this was acceptable?


>
> Takashi
>