Re: [PATCH 1/4] ALSA: hda/realtek: fix mute/micmute LEDs for HP 855 G8

[Alexander Sergeyev <sergeev917@gmail.com>]

On Mon, Jan 31, 2022 at 03:57:04PM +0100, Takashi Iwai wrote:
> > IO_PAGE_FAULTs go away with CONFIG_IOMMU_DEFAULT_PASSTHROUGH enabled. As I 
> > understand, this leads to reduced DMA device isolation which is generally 
> > not desirable. I was initially thinking about races between some delayed 
> > code and io-memory pages unmapping, but first IO_PAGE_FAULTs (running 
> > non-passthrough iommu) happen during bind operations as well.

> I still don't get what really triggers it.  This won't happen when you
> build modules and load/unload the driver instead of dynamic binding?

I've built snd_hda_intel as a module, everything else is left built-in.
The initial modprobe and rmmod were clean, but the subsequent modprobe gave 
IO_PAGE_FAULT.

# modprobe snd-hda-intel
snd_hda_intel 0000:05:00.1: bound 0000:05:00.0 (ops amdgpu_dm_audio_component_bind_ops)
input: HD-Audio Generic HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:08.1/0000:05:00.1/sound/card0/input24
input: HD-Audio Generic HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:08.1/0000:05:00.1/sound/card0/input25
input: HD-Audio Generic HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:08.1/0000:05:00.1/sound/card0/input26
input: HD-Audio Generic HDMI/DP,pcm=9 as /devices/pci0000:00/0000:00:08.1/0000:05:00.1/sound/card0/input27
snd_hda_codec_realtek hdaudioC1D0: autoconfig for ALC285: line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:speaker
snd_hda_codec_realtek hdaudioC1D0:    speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
snd_hda_codec_realtek hdaudioC1D0:    hp_outs=1 (0x21/0x0/0x0/0x0/0x0)
snd_hda_codec_realtek hdaudioC1D0:    mono: mono_out=0x0
snd_hda_codec_realtek hdaudioC1D0:    inputs:
snd_hda_codec_realtek hdaudioC1D0:      Mic=0x19
snd_hda_codec_realtek hdaudioC1D0:      Internal Mic=0x12
snd_hda_intel 0000:05:00.6: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0015 address=0x1fffff800 flags=0x0020]