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| author | Harsha Priya <harshapriya.n@intel.com> | 2020-07-06 23:53:17 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2020-07-07 13:42:35 +0300 |
| commit | 951894cf30f417443d9e0eda33312613c2a7edf6 (patch) | |
| tree | b97a2612992fd82727960f3c50dbf495c944bb8f /sound/pci/hda/Kconfig | |
| parent | ad1e0b7de0cc6f6670b3ffc279cb587a90ce4d47 (diff) | |
| download | linux-951894cf30f417443d9e0eda33312613c2a7edf6.tar.xz | |
ALSA: hda/hdmi: Add Intel silent stream support
External HDMI receivers have analog circuitry that needs to be powered-on
when exiting standby, and a mechanism to detect PCM v. IEC61937 data.
These two steps take time and up to 2-3 seconds of audio may be muted
when starting playback.
Intel hardware (Haswell and beyond) can keep the link active
with a 'silent stream', so that the receiver does not go through those
two steps when valid audio is transmitted. This mechanism relies
on an setting the channel_id as 0xf, sending info packet and preventing
the codec from going to D3, which will increase the platform
static power consumption. The info packet assumes a basic 2ch stereo,
and the silent stream is enabled when connecting a monitor.
In case of format changes the detection of PCM v. IEC61937 needs to
be re-run. In this case there is no way to avoid the 2-3s mute.
The silent stream is enabled with a Kconfig option, as well as a kernel
parameter should there be a need to override the build time default.
This approach is used based on the power_save capability as an example,
but in the future, it may be used with a kcontrol,
depending on UCM support for HDaudio legacy.
Signed-off-by: Harsha Priya <harshapriya.n@intel.com>
Signed-off-by: Emmanuel Jillela <emmanuel.jillela@intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/1594068797-14011-1-git-send-email-harshapriya.n@intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/pci/hda/Kconfig')
| -rw-r--r-- | sound/pci/hda/Kconfig | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/sound/pci/hda/Kconfig b/sound/pci/hda/Kconfig index 102ef58c49e4..90759391cbac 100644 --- a/sound/pci/hda/Kconfig +++ b/sound/pci/hda/Kconfig @@ -240,6 +240,20 @@ config SND_HDA_POWER_SAVE_DEFAULT The default time-out value in seconds for HD-audio automatic power-save mode. 0 means to disable the power-save mode. +config SND_HDA_INTEL_HDMI_SILENT_STREAM + bool "Enable Silent Stream always for HDMI" + depends on SND_HDA_INTEL + help + Intel hardware has a feature called 'silent stream', that + keeps external HDMI receiver's analog circuitry powered on + avoiding 2-3 sec silence during playback start. This mechanism + relies on setting channel_id as 0xf, sending info packet and + preventing codec D3 entry (increasing platform static power + consumption when HDMI receiver is plugged-in). 2-3 sec silence + at the playback start is expected whenever there is format change. + (default is 2 channel format). + Say Y to enable Silent Stream feature. + endif endmenu |