On 9/24/19 12:29 PM, Jaroslav Kysela wrote:
Dne 24. 09. 19 v 15:41 Pierre-Louis Bossart napsal(a):
On 9/24/19 1:46 AM, Jaroslav Kysela wrote:
Dne 24. 09. 19 v 1:34 Pierre-Louis Bossart napsal(a):
On 9/23/19 4:21 PM, Takashi Iwai wrote:
On Mon, 23 Sep 2019 22:35:14 +0200,
Jaroslav Kysela wrote:
Dne 23. 09. 19 v 20:24 Pierre-Louis Bossart napsal(a):
On 9/23/19 11:57 AM, Jaroslav Kysela wrote:
There are basically three drivers for the PCI devices for
the recent Intel hardware with the build-in DSPs. The legacy HDA
driver has dmic_detect module option for the auto detection
of the platforms with the digital microphone. Because the SOF
driver is preferred, just skip PCI probe in the Skylake SST
driver when the PCI device ID clashes by default. The user
can override the auto behaviour with the pci_binding
module parameter.
Thanks Jaroslav for re-opening this mutual-exclusion issue.
I think we want to deal with this in two alternate ways
1. static built-time exclusion based on Kconfigs
Unfortunately, that's really an issue for the universal distros.
Right. The Kconfig of Intel audio is already too messy even for now.
We don't want more complexity just for covering some very corner
case.
Practically seen, if SOF Kconfig is enabled, we may assume that SOF is
preferred in general. I don't think of any big need of yet another
static configuration.
2. probe-time exclusion based on quirks (CPU ID + DMI)
For example with a SKL/KBL/APL chromebook w/ DMIC we'd want to use the
SST driver and for GLK+ we want to use SOF. For any device with
HDAudio+DMIC we'd want SOF, same for any device with SoundWire when it's
fully supported.
I can't recall if I shared the patches I worked on a couple of months
ago, but they are still at https://github.com/thesofproject/linux/pull/927
Thanks for pointing me to this. It does not address the legacy HDA, but it's a
step forward.
The legacy HD-audio stuff is resolved with the recent DMIC detection
on 5.4, I suppose?
Unfortunately not completely. The Broxton and Coffelake PCI IDs are also
shared by the SST / Legacy HDA drivers, so the universal kernel will be
confused (at least snd_hda_intel will be loaded as first).
I don't see any issues with this. The use of the DSP is only required
when DMICs/I2S/SoundWire are used, or the firmware contains processing.
Using the firmware is passthrough mode brings no added value.
If the only thing that's done is manage an HDaudio link, the legacy is
just fine.
Yes, but the dependancy on the PCI probe order specified just by the module
name is not really nice at all. We are just lucky that the legacy
snd_hda_intel is first.
the first part essentially does the same thing as this patch, the second
relies on quirks. I've been busy with other things but indeed it's high
time we closed this for distributions.
Yes, and I have to say, it's too late for the hardware vendors right now. I
will probably apply my patch to our distribution (I don't care too much about
chromebooks - the user can change the module/driver behaviour manually) until
we have a better code.
Boot log from Lenovo Carbon X1 (7th gen) with the default settings:
snd_hda_intel 0000:00:1f.3: Digital mics found on Skylake+ platform, aborting probe
snd_soc_skl 0000:00:1f.3: SOF driver is preferred on this platform, aborting probe
sof-audio-pci 0000:00:1f.3: warning: No matching ASoC machine driver found
sof-audio-pci 0000:00:1f.3: DSP detected with PCI class/subclass/prog-if 0x040380
....
Perhaps, it may be more wise to create one shared module and all
three drivers should call the driver detection routine(s) from one
place.
We did look into this and it's a bit complicated in terms of plumbing.
Could you elaborate more here? I believe that for the runtime environment
where all drivers are compiled in the kernel, it might make sense to have this
code at one place and installed only once for all three (or may be four in the
soundwire future) drivers.
We should have one straight way which driver/module is used. The separate
conditions in the mentioned drivers will cause problems. Also, it will
simplify things for the end user. One module parameter (in the driver selector
library) is better than three or four to make things working (if the DMI /
whatever table is not preset correctly for the new hardware).
Well, one question is where to put this option. I thought of HD-audio
core in the past, but it's not always the common place any longer.
We may introduce yet another common module just for an option, but it
sounds little appealing to me in comparison with the needed
resources.
Basically the deployment of SST is only for the already existing
devices, and all newer should go for SOF. And, the pattern Pierre
mentioned should cover almost all use cases. This made me believing
that a simple switch is no mandatory request.
In anyway, Jaroslav's patch looks like a good starting point. We can
build up a few more exceptions (SKl/KBl/APL Chromebooks with DMIC) on
top of it, then we've done mostly, right?
Yes, there are only a handful of quirks really.
It seems like a not very rubust solution for me. If you don't like to have
a standalone module, the code might be included to all drivers, but we losethe
possibility to control the auto detection behaviour from the one place
(one module parameter).
Perhaps, we can rename snd_intel_nhlt() module and put the auto-detection code
there. It's required by all mentioned drivers, so the extra resources required
for this new code are minimal.
it's kinda what my patches were about, there was a central set of quirks
in sound/soc/intel/common called by SOF/SST drivers.
Yes, but no legacy HDA... I can expect that we want to use DSP to enable some
effects or decoders on hardware which has this co-processor in the near future.
I don't disagree, but I have more modest goals for the near future.
There are quite a few intermediate steps to make before enabling fancy
processing, with the transition to HDAudio+DMICs there are multiple gaps
in the stack, e.g. the dependency on UCM, support for mute buttons and
LEDs, hardware volumes handled by PulseAudio, firmware/topologies pushed
to distributions with packages, etc.
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