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

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Date:   Sat, 22 Jan 2022 22:05:22 +0300
From:   Alexander Sergeyev <sergeev917@...il.com>
To:     Takashi Iwai <tiwai@...e.de>
Cc:     Jeremy Szu <jeremy.szu@...onical.com>, tiwai@...e.com,
        "moderated list:SOUND" <alsa-devel@...a-project.org>,
        Kailang Yang <kailang@...ltek.com>,
        open list <linux-kernel@...r.kernel.org>,
        Huacai Chen <chenhuacai@...nel.org>,
        Jian-Hong Pan <jhp@...lessos.org>,
        Hui Wang <hui.wang@...onical.com>,
        PeiSen Hou <pshou@...ltek.com>
Subject: Re: [PATCH 1/4] ALSA: hda/realtek: fix mute/micmute LEDs for HP 855
 G8

On Wed, Jan 19, 2022 at 12:32:51PM +0300, Alexander Sergeyev wrote:
> No, I mean "IO_PAGE_FAULT" and "out of range cmd" don't appear on every 
> unbind & bind. Sometimes it works cleanly.

Unbind & bind generally works without error messages on the first attempt. The 
second unbind & bind tends to generate io page faults like "AMD-Vi: Event 
logged [IO_PAGE_FAULT ...]", but might work fine as well.

In some cases "snd_hda_codec_realtek: out of range cmd" errors are triggered in 
addition to io page faults.

> This seems to be a bogus COEF. But I have no idea from where this
> comes. The values look completely wrong.

In such cases unexpected COEF values are coming from COEF reads during 
read/write pairs that implement update operations.

For example (these traces are from added printk statements):

alc_update_coef_led(codec, led {.idx=0x19, .mask=0x2000, .on=0x2000, .off=0x0}, polarity=0, on=1)
alc_update_coefex_idx(codec, nid, coef_idx=0x19, mask=0x2000, bits_set=0x2000)
alc_update_coef_led(codec, led {.idx=0xb, .mask=0x8, .on=0x8, .off=0x0}, polarity=0, on=1)
alc_update_coefex_idx(codec, nid, coef_idx=0xb, mask=0x8, bits_set=0x8)
snd_hdac_codec_write(hdac, nid, flags=0, verb=0x500, parm=0x19) = 0x0
snd_hdac_codec_write(hdac, nid, flags=0, verb=0x500, parm=0xb) = 0x0
snd_hdac_codec_read(hdac, nid, flags=0, verb=0xc00, parm=0x0) = 0x90170110
alc_update_coefex_idx: alc_read_coefex_idx(codec, nid, coef_idx=0xb) returned 0x90170110
alc_update_coefex_idx: calling alc_write_coefex_idx(codec, nid, coef_idx=0xb, coef_val=0x90170118)
snd_hdac_codec_read(hdac, nid, flags=0, verb=0xc00, parm=0x0) = 0x0
alc_update_coefex_idx: alc_read_coefex_idx(codec, nid, coef_idx=0x19) returned 0x0
alc_update_coefex_idx: calling alc_write_coefex_idx(codec, nid, coef_idx=0x19, coef_val=0x2000)
snd_hdac_codec_write(hdac, nid, flags=0, verb=0x500, parm=0xb) = 0x0
snd_hda_codec_realtek hdaudioC1D0: out of range cmd 0:20:400:90170118
snd_hdac_codec_write(hdac, nid, flags=0, verb=0x400, parm=0x90170118) = 0xffffffff

Then I've specifically added printk on alc_update_coefex_idx entry and exit:

[4.036211] alc_update_coefex_idx(codec, nid, coef_idx=0x10, mask=0x200, bits_set=0x0): entering
[4.036503] alc_update_coefex_idx(codec, nid, coef_idx=0x10, mask=0x200, bits_set=0x0): exiting
[4.036543] alc_update_coefex_idx(codec, nid, coef_idx=0xb, mask=0x8, bits_set=0x0): entering
[4.036546] alc_update_coefex_idx(codec, nid, coef_idx=0x19, mask=0x2000, bits_set=0x0): entering
[4.037139] alc_update_coefex_idx(codec, nid, coef_idx=0xb, mask=0x8, bits_set=0x0): exiting
[4.037609] alc_update_coefex_idx(codec, nid, coef_idx=0x19, mask=0x2000, bits_set=0x0): exiting

I'm not sure about kernel log buffering or maybe the device support for 
pipelining, but is it okay that alc_update_coefex_idx() seem to overlap?