From 2a2edfbbfee47947dd05f5860c66c0e80ee5e09d Mon Sep 17 00:00:00 2001 From: Kai Vehmanen Date: Tue, 29 Oct 2019 15:40:09 +0200 Subject: ALSA: hda/hdmi - implement mst_no_extra_pcms flag To support the DP-MST multiple streams via single connector feature, the HDMI driver was extended with the concept of backup PCMs. See commit 9152085defb6 ("ALSA: hda - add DP MST audio support"). This implementation works fine with snd_hda_intel.c as PCM topology is fully managed within the single driver. When the HDA codec driver is used from ASoC components, the concept of backup PCMs no longer fits. For ASoC topologies, the physical HDMI converters are presented as backend DAIs and these should match with hardware capabilities. The ASoC topology may define arbitrary PCMs (i.e. frontend DAIs) and have processing elements before eventual routing to the HDMI BE DAIs. With backup PCMs, the link between FE and BE DAIs would become dynamic and change when monitors are (un)plugged. This would lead to modifying the topology every time hotplug events happen, which is not currently possible in ASoC and there does not seem to be any obvious benefits from this design. To overcome above problems and enable the HDMI driver to be used from ASoC, this patch adds a new mode (mst_no_extra_pcms flags) to patch_hdmi.c. In this mode, the codec driver does not assume the backup PCMs to be created. Signed-off-by: Kai Vehmanen Reviewed-by: Takashi Iwai Reviewed-by: Pierre-Louis Bossart Link: https://lore.kernel.org/r/20191029134017.18901-2-kai.vehmanen@linux.intel.com Signed-off-by: Mark Brown --- include/sound/hda_codec.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/sound/hda_codec.h') diff --git a/include/sound/hda_codec.h b/include/sound/hda_codec.h index 9a0393cf024c..ac18f428eda6 100644 --- a/include/sound/hda_codec.h +++ b/include/sound/hda_codec.h @@ -254,6 +254,7 @@ struct hda_codec { unsigned int force_pin_prefix:1; /* Add location prefix */ unsigned int link_down_at_suspend:1; /* link down at runtime suspend */ unsigned int relaxed_resume:1; /* don't resume forcibly for jack */ + unsigned int mst_no_extra_pcms:1; /* no backup PCMs for DP-MST */ #ifdef CONFIG_PM unsigned long power_on_acct; -- cgit v1.2.3