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| author | Kai Vehmanen <kai.vehmanen@linux.intel.com> | 2022-02-16 20:24:05 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2022-02-17 11:46:01 +0300 |
| commit | 15175a4f2bbbcbadb1a40098b6dcff0467300e99 (patch) | |
| tree | 4fbed905e9f435114653082cacc7fdb9d1cc0c4d /sound/pci/hda/Kconfig | |
| parent | a9f73b06ff913da374d257d933a1cf9bfbc84743 (diff) | |
| download | linux-15175a4f2bbbcbadb1a40098b6dcff0467300e99.tar.xz | |
ALSA: hda/hdmi: add keep-alive support for ADL-P and DG2
Implement HDA keep alive (KAE) support for Intel display codecs. When no
audio stream is active, the display codec will provide a continuous clock
and a valid but silent audio stream to any connected HDMI/DP receiver.
Without this, upon starting a new playback stream, initial samples may be
lost as many receivers require time to initialize for new clock.
This is a new feature in Intel AlderLake-P display codec implementation
and replaces the Intel i915 silent-stream extension that has been used
on older hardware. Main benefit of the new method is that codec no longer
needs to be kept in D0 power state.
This patch depends on commit 112a87c48e83 ("drm/i915/display: program
audio CDCLK-TS for keepalives").
[ a minor coding-style fix by tiwai ]
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Jyri Sarha <jyri.sarha@intel.com>
Link: https://lore.kernel.org/r/20220216172405.3994959-1-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/pci/hda/Kconfig')
| -rw-r--r-- | sound/pci/hda/Kconfig | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/sound/pci/hda/Kconfig b/sound/pci/hda/Kconfig index febe1c2b7d9a..9f6c99c1d87b 100644 --- a/sound/pci/hda/Kconfig +++ b/sound/pci/hda/Kconfig @@ -285,15 +285,16 @@ 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. + Say Y to enable HD-Audio Keep Alive (KAE) aka Silent Stream + for HDMI on hardware that supports the feature. + + When enabled, the HDMI/DisplayPort codec will continue to provide + a continuous clock and a valid but silent data stream to + any connected external receiver. This allows to avoid gaps + at start of playback. Many receivers require multiple seconds + to start playing audio after the clock has been stopped. + This feature can impact power consumption as resources + are kept reserved both at transmitter and receiver. endif |