Hi Guys, We have received reports that on some Kabylake laptops (Acer Swift SF314-54/55 and Lenovo Yoga C930...etc), all sound cards no longer be detected after upgrade to kernel later than 5.8. These laptops have one thing in common, all of them have Realtek audio codec and connect the internal microphone to DMIC of the Intel SST controller either [8086:9d71] or [8086:9dc8]. Please refer to https://bugzilla.kernel.org/show_bug.cgi?id=201251#c246 and https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1915117.
From the dmesg from kernel 5.8, the sound related parts only show as follows but the expected snd_hda_codec_realtek and the snd_soc_skl are not even loaded then. [ 13.357495] snd_hda_intel 0000:00:1f.3: DSP detected with PCI class/subclass/prog-if info 0x040100 [ 13.357500] snd_hda_intel 0000:00:1f.3: Digital mics found on Skylake+ platform, using SST driver
Building the kernel with the CONFIG_SND_SOC_INTEL_KBL removed can load the snd_hda_codec_realtek successfully and the pulseaudio and alsa-utils can detect the sound cards again. The result of bisecting between kernel 5.4 and 5.8 also get similar result, reverting the commit "ALSA: hda: Allow SST driver on SKL and KBL platforms with DMIC" can fix the issue. I tried to generate the required firmware for snd_soc_skl but it did not help. Please refer to what I did in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1915117/comments/14 and https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1915117/comments/18.
Since the skl_hda_dsp_generic-tplg.bin and dfw_sst.bin are not in the linux-firmware. The Intel SST support for Skylake family is not yet complete. Can we simply revert the "ALSA: hda: Allow SST driver on SKL and KBL platforms with DMIC" in the current stage and wait for SOF support for Skylake family? Or please suggest a better solution for this. Thanks
Chris