On 3/15/17 10:28 AM, Ian W MORRISON wrote:
On 16 March 2017 at 00:54, Pierre-Louis Bossart
<pierre-louis.bossart@xxxxxxxxxxxxxxx
<mailto:pierre-louis.bossart@xxxxxxxxxxxxxxx>> wrote:
On 3/15/17 1:34 AM, 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
<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.
By defining the default of the two associated CONFIG settings
(SND_X86
and HDMI_LPE_AUDIO) as a module, upstream kernel builds would
automatically provide the much desired HDMI audio support by
default.
I have mixed feelings about this. This would make the life of some
distros easier but at the same time it's not needed by everyone,
e.g. Chrome does not need this, the skews they use have the HDaudio
output.
Likewise none of the SST-based machine drivers are selected by
default, so distros already have to select what they want to
support, and it's no big deal for them to select this option while
they are at it.
I am not going to fight this patch but I feel it's a bit
inconsistent with how other options are enabled. If it was really
helpful to select modules by default then we should also select all
the SST options. If it's not then nothing is selected by default.
I did consider arguing that as 'HDMI', 'SND_SOC_HDMI_CODEC', 'DRM' and
'DRM_I915' are set presumably as video and audio are seen as a function
of the OS rather than only being enabled by a distro. So adding
'HDMI_LPE_AUDIO' was in keeping with concept of the OS providing core
functionality that a distro could disable it if required. But I thought
that might distract from the purpose of the patch and needlessly provoke
discussion!
I too looked at the current state which I found to be inconsistent. For
example a default config built currently sets
'SND_SOC_INTEL_BYT_RT5640_MACH=m' which in turn then sets
'SND_SOC_INTEL_BAYTRAIL=m' and 'SND_SOC_INTEL_SST=m' among others.
Likewise 'PINCTRL_BAYTRAIL=y' is set whereas 'PINCTRL_CHERRYVIEW' isn't.
Again I didn't want to open a can of worms as I've not fully identified
the extent of the inconsistencies and again it might detract from the
purpose of the patch.
I concluded that it was better to provide audio over HDMI by default for
the simple reason that distros may not add it because they didn't see
the need or might even overlooked it and that they could always exclude
it if they had a reason. The primary goal being to make the provision of
audio for BYT and CHT devices as simple and as quick possible.
Objection withdrawn. There are two audio interfaces for HDMI, and
HDaudio is enabled by default so we should do the same for the LPE_AUDIO
mode. Also the DRM part does the detection unconditionally so we might
as well support both modes.
This patch uses a Kconfig 'default' statement to include the
driver as
default.
Signed-off-by: Ian W Morrison <linuxium@xxxxxxxxxxxxxxx
<mailto:linuxium@xxxxxxxxxxxxxxx>
<mailto:linuxium@xxxxxxxxxxxxxxx <mailto:linuxium@xxxxxxxxxxxxxxx>>>
---
sound/x86/Kconfig | 2 ++
1 file changed, 2 insertions(+)
diff --git a/sound/x86/Kconfig b/sound/x86/Kconfig
index 84c8f8fc..439850c 100644
--- a/sound/x86/Kconfig
+++ b/sound/x86/Kconfig
@@ -1,6 +1,7 @@
menuconfig SND_X86
tristate "X86 sound devices"
depends on X86
+ default m
---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 m
select SND_PCM
help
Choose this option to support HDMI LPE Audio mode
--
1.9.1
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