On Thu, 29 Aug 2019 15:53:41 +0200, Kai Vehmanen wrote:
Hi all, here's a RFC patch series that adapts SOF (and one example machine driver) to use snd-hda-codec-hdmi (patch_hdmi.c) codec driver instead of hdac_hdmi (soc/codecs/hdac_hdmi.c). The primary goal is unify the HDMI codec implementation between DSP and non-DSP HDA configurations, offer same interface to user-space and reduce maintenance load for all.
Main points I'd like your input on:
- Is the high-level approach ok?
- SOF already uses pci/hda/ for all others codecs, so HDMI has been the sole exception where code has been duplicated.
- I've tried to keep changes to hda/hdmi minimal.
- This series implements logic to parse the PCM topology in a dynamic fashion, so we do not have to change all existing (and future) DSP topologis to use fixed PCM device numbers for HDMI, and we avoid need to hardcode PCM device numbers in machine driver code.
- Can we drop hdac_hdmi and its support from machine drivers, or do we need to make it optional and keep it around?
- Current series does not add any Kconfig options, but simply switches SOF to use HDA codecs for all, including HDMI/DP. This means hdac_hdmi is never used with SOF and could be dropped (if SST is ok as well).
- This may break some usage with SST (input is welcome!)
- The change is visible to applications. The ALSA mixer interface is different (OTOH with the new driver, playback works out-of-the-box while with hdac_hdmi you needed to set the multiple controls first, to have any audio out).
- Alternatively I could add a KConfig option and we could have a deprecation period for hdac_hdmi, allowing people to compile with the old driver during transition time. This will require #ifdef'ing in all the machine drivers.
.. once these are addressed, I can proceed to extend the patchset with all affected machine drivers.
Feature and testing info:
- Tested on multiple Intel platforms supported by SOF.
- Tested with ALSA console tools as well as with Pulseaudio.
- requires Pulseaudio 12.x or newer, see https://lists.freedesktop.org/archives/pulseaudio-discuss/2019-August/031358...
- HDMI, DP, DP-MST with multi-monitor use-scenarios work ok.
- New feature for SOF: ELD /proc fs works just like in DSP-less mode.
- New feature for SOF: jack detection works out-of-the-box with Pulseaudio (no need for card specific UCM for HDMI)
- Pre-reviewed at: https://github.com/thesofproject/linux/pull/1155
IMO, the only and the most important point is whether it works as-is without changing the existing user-space, or exactly what scenario would be broken. If the breakage is significant, we may introduce a Kconfig, as you suggested.
I don't think the mixer contents change are problematic. In the case of HDMI/DP, it's mostly read-only for fetching ELD or jack state.
Other than that, I like the idea, the code change looks simple enough, and it'd make maintenance easier.
thanks,
Takashi
Kai Vehmanen (7): ALSA: hda - add mst_no_extra_pcms flag to hda_codec ASoC: Intel: skl-hda-dsp-generic: use snd-hda-codec-hdmi ASoC: hdac_hda: add support for HDMI/DP as a HDA codec ALSA: hda/hdmi - allow control creation without a linked pcm ALSA: hda/hdmi - implement mst_no_extra_pcms flag ALSA: hda/hdmi - complete pcm_setup_pin without snd_pcm link ASoC: SOF: Intel: load hda codec module also for HDMI/DP
include/sound/hda_codec.h | 1 + sound/pci/hda/patch_hdmi.c | 31 ++++--- sound/soc/codecs/hdac_hda.c | 95 +++++++++++++++++--- sound/soc/codecs/hdac_hda.h | 10 ++- sound/soc/intel/boards/skl_hda_dsp_common.c | 27 ++---- sound/soc/intel/boards/skl_hda_dsp_common.h | 61 +++++++++++++ sound/soc/intel/boards/skl_hda_dsp_generic.c | 7 -- sound/soc/sof/intel/hda-codec.c | 11 +-- sound/soc/sof/intel/hda.h | 5 +- 9 files changed, 189 insertions(+), 59 deletions(-)
-- 2.17.1