On 9/12/22 14:42, Pierre-Louis Bossart wrote:
On 12/9/22 01:37, Péter Ujfalusi wrote:
On 08/12/2022 18:37, Pierre-Louis Bossart wrote:
On 12/8/22 10:17, Mark Brown wrote:
On Thu, Dec 08, 2022 at 02:02:02PM +0000, Joakim Tjernlund wrote:
Several of our Lenovo laptops lost PC audio output in Teams in 5.15.81(also in 5.15.82) Revering above patch:https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=l... fixes it.
Any idea what the real fix is?
Adding the Intel people. I've no idea if there's issues with dependencies, missing quirks for the hardare or anything in that stable version.
Humm, yes in the past we used the TDM masks to convey the 'stream_tag' for HDaudio.
I can still see this in v5.15.85 in sound/soc/sof/intel/hda-dai.c
/* set the stream tag in the codec dai dma params */ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) snd_soc_dai_set_tdm_slot(codec_dai, stream_tag, 0, 0, 0); else snd_soc_dai_set_tdm_slot(codec_dai, 0, stream_tag, 0, 0);
That was changed in 636110411ca72 ASoC: Intel/SOF: use set_stream() instead of set_tdm_slots() for HDAudio
snd_soc_dai_set_stream(codec_dai, hdac_stream(hext_stream), substream->stream);
So my guess is that zeroing out TDM masks has a side effect on older stable kernels, and that effect is not seen on newer kernels.
I don't really understand what the side effect might be though.
The reason is that on the the tdm mask now became persistent and the HDA code relied on the fact that it is volatile, it is reset for each stream open. The core would do some fixup if the tx/rx_mask is set: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/sound/... https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/sound/...
This did not happened when the tx/rx_mask was reset at open - and later set bny the HDA driver, I guess after these checks, so the fixup did not happened, but without resetting them we would use the previously set masks to do fixups for the number of channels (!) based on a stream_tag value, which has nothing to do with channels.
Agree with the analysis, so what would be the least bad recommendation? a) revert the "don't zero TDM masks" patch b) backport the change to use set_stream()?
Adding alsa-devel@alsa-project.org and patches@opensource.cirrus.com. Please add relevant lists when sending emails so that other people who might need to know, or have an opinion, are aware of the discussion.