On 5/6/22 08:39, Cezary Rojewski wrote:
On 2022-05-06 3:12 PM, Mark Brown wrote:
On Wed, Apr 27, 2022 at 10:47:12AM -0500, Pierre-Louis Bossart wrote:
On 4/27/22 03:18, Cezary Rojewski wrote:
Add generic ASoC equivalent of ALSA HD-Audio codec. This codec is designed to follow HDA_DEV_LEGACY convention. Driver wrapps existing hda_codec.c handlers to prevent code duplication within the newly added
I am surprised the explanations don't even mention the existence of hdac_hda.c
I thought the series was about adding machine drivers, but this also adds code on the sound/soc/codecs/ side which I didn't see coming.
I am not qualified to review this part of the code, I just wonder about duplication of functionality.
At the very least an explanation on why you decided to NOT use hdac_hda.c would be useful to reviewers and maintainers.
Right, why the duplication here? Can't we fix or extend the existing code to do whatever it's not currently doing which compels reimplementation?
Sorry for the late response, did not realize there is an unanswered comment here.
So, the rough list goes as:
- hdac_hda.c hardcodes codec capabilities rather than aligning with what
sound/pci/hda/ code does
- merges HDMI (i.e. Intel i915 audio component) and HDA DAIs together
whereas these are two separate devices
- because of above, implements custom search/matching mechanism for PCM/DAI
- cont. because of above, its header hosts private data struct,
unnecessary complication
- follows HDA_DEV_ASOC convention rather than HDA_DEV_LEGACY causing
misalignments between sound/pci/hda and sound/soc/ behaviour
- has basic PM runtime support and does not survive scenarios where
resume/suspend + denylist + rmmod/modprobe are mixed together or invoked in unordered fashion between this module and several others in the audio stack
My suggestion is different: have all HD-Audio ASoC users switch to this implementation when possible and remove the existing code along with skylake-driver.
I am not against change and will agree that HDaudio support is far from perfect, but it's been released for multiple generations from dozens of OEMs and mostly works. All the issues reported to us are related to codec configurations that also don't work with the legacy HDaudio driver, DMIC configurations, CSME authentication or system hangs that have not been root-caused [1]. HDaudio/ASoC interfaces are not on our radar as problematic.
Disrupting basic HDaudio support to do things better has to be handled with extreme caution and a ton of testing involving distro maintainers and community members, so we are talking about an opt-in transition, not an immediate switch. We've done a similar transition in the past to stop using a dedicated hdac_hdmi.c codec, see all references to the 'use_common_hdmi' parameter in the SOF code. That transition seems to go exactly against your second point above on HDMI and HDA being different devices, so this could be an interesting debate.
Changes to the HDAudio/ASoC support would need to be handled with a separate patchset anyways, and the SOF side changes done after we are finished with the IPC4 and MeteorLake upstreaming. No one in our team has any bandwidth to help with reviews or tests on this topic at the moment.
I will also re-state that the removal of the skylake driver can only happen after a long period of deprecation, when firmware and topologies have been picked by distributions and all users are known to have switched, so it's very likely that any alignment between "all HD-Audio ASoC users" mentioned above does include the Skylake driver, doesn't it?
So to circle back: is there anything preventing the use of the existing hdac_hda.c codec in this "ASoC: Intel: avs: Machine boards and HDA codec support" series and can the HDaudio codec change be done "later" in a more organized way?
Thanks! -Pierre
[1] https://github.com/thesofproject/linux/issues?q=is%3Aissue+is%3Aopen+label%3...