Re: ThinkPad T480s & LED_MUTE, LED_MICMUTE

["Pali Rohár" <pali.rohar@gmail.com>]

On Monday 18 June 2018 13:21:21 Pali Rohár wrote:
> On Monday 18 June 2018 12:36:31 Takashi Iwai wrote:
> > On Mon, 18 Jun 2018 12:28:06 +0200,
> > Pali Rohár wrote:
> > > 
> > > On Saturday 16 June 2018 18:02:14 Takashi Iwai wrote:
> > > > On Sat, 16 Jun 2018 17:43:09 +0200,
> > > > Pali Rohár wrote:
> > > > > 
> > > > > On Saturday 16 June 2018 09:05:41 Takashi Iwai wrote:
> > > > > > On Fri, 15 Jun 2018 21:09:59 +0200,
> > > > > > Pali Rohár wrote:
> > > > > > > 
> > > > > > > On Friday 15 June 2018 14:51:47 Takashi Iwai wrote:
> > > > > > > > On Fri, 08 Jun 2018 13:10:57 +0200,
> > > > > > > > Pali Rohár wrote:
> > > > > > > > > 
> > > > > > > > > Hi! With up-to-date thinkpad_acpi.ko driver on ThinkPad T480s I'm seeing
> > > > > > > > > a strange behavior of LEDs which are integrated into mic mute (Fn+F4)
> > > > > > > > > and mute (Fn+F1) keys.
> > > > > > > > > 
> > > > > > > > > When thinkpad_acpi.ko is not loaded, then mute key is working fine. When
> > > > > > > > > pressed, it correctly generates KEY_MUTE on AT Translated Set 2 keyboard
> > > > > > > > > input device and also turn on/of mute led. But when micmute key is
> > > > > > > > > pressed then, nothing happen. No key event is reported and also led is
> > > > > > > > > not turned on/off.
> > > > > > > > > 
> > > > > > > > > On the other hand, when thinkpad_acpi.ko is loaded, then both buttons
> > > > > > > > > mute and micmute correctly generates input events; mute via AT keyboard
> > > > > > > > > and micmute via ThinkPad Extra Buttons. But led is not changed. When
> > > > > > > > > thinkpad_acpi.ko is loaded it turn off both leds (mute and micmute) and
> > > > > > > > > leds after pressing any of those buttons, leds are not turned on again.
> > > > > > > > > 
> > > > > > > > > When thinkpad_acpi.ko is unloaded, then pressing mute button again start
> > > > > > > > > switching led on/off.
> > > > > > > > > 
> > > > > > > > > So it seems that some init sequence of thinkpad_acpi.ko breaks mute led.
> > > > > > > > > And fini sequence of thinkpad_acpi.ko makes mute led working again.
> > > > > > > > 
> > > > > > > > Usually the mute LED on Thinkpad is triggered from HD-audio driver
> > > > > > > > (sound/pci/hda/thinkpad_helper.c), and it's a soft-bound via
> > > > > > > > symbol_request(tpacpi_led_set).  I thought thinkpad_acpi is
> > > > > > > > auto-loaded when the module gets bound.
> > > > > > > > 
> > > > > > > > A possible explanation would be that TPT480s has neither IBM0068,
> > > > > > > > LEN0068 nor LEN0268 ACPI HIDs, hence the driver is not auto-loaded.
> > > > > > > 
> > > > > > > I have Debian Stretch kernel (4.9) which does not have LEN0268 alias for
> > > > > > > thinkpad_acpi.ko. So thinkpad_acpi.ko is not loaded automatically. But I
> > > > > > > have put thinkpad_acpi into /etc/modules and it is now automatically
> > > > > > > loaded at boot.
> > > > > > 
> > > > > > That's odd.  It's exposed via
> > > > > >   MODULE_DEVICE_TABLE(acpi, ibm_htk_device_ids);
> > > > > > 
> > > > > > It's been already in 4.9.  At this point, something is fishy.
> > > > > 
> > > > > $ /sbin/modinfo thinkpad_acpi | grep alias
> > > > > alias:          dmi:bvnIBM:bvrI[MU]ET??WW*
> > > > > alias:          tpacpi
> > > > > alias:          acpi*:LEN0068:*
> > > > > alias:          acpi*:IBM0068:*
> > > > > 
> > > > > No there is no LEN0268 on 4.9.
> > > > 
> > > > OK, that's the cause.  It's really old.
> > > > 
> > > > The commit a3c42a467a25 ("platform/x86: thinkpad_acpi: Adding new
> > > > hotkey ID for Lenovo thinkpad") has to be backported.
> > > 
> > > This commit just autoloads thinkpad_acpi driver, right? So manual
> > > modprobe (for now) is OK too?
> > 
> > Well, the manual modprobe is superfluous if it's properly bound with
> > HD-audio driver.  The HD-audio driver calls symbol_request(), so it
> > should do modprobe by itself.
> > 
> > > > Also, in the HD-audio side, the commit 2ecb704a1290 ("ALSA: hda - add
> > > > a new condition to check if it is thinkpad") is needed, too.
> > > 
> > > This commit was introduced in 4.9 and Debian kernel has it. I looked
> > > into Debian source code and there is check for LEN0268 in file
> > > sound/pci/hda/thinkpad_helper.c
> > 
> > Then check whether the function gets really called.
> 
> Checked, no it is not called.
> 
> Now I see that snd_hda_codec_generic is visible in lsmod and thinkpad
> helper is compiled only into snd-hda-codec-realtek and
> snd-hda-codec-conexant... Therefore nobody is even trying to use that
> function.

Interesting is this part:

$ head /proc/asound/card0/codec#0
Codec: Realtek ALC257
Address: 0
AFG Function Id: 0x1 (unsol 1)
Vendor Id: 0x10ec0257
Subsystem Id: 0x17aa2258
Revision Id: 0x100001
No Modem Function Group found
Default PCM:
    rates [0x560]: 44100 48000 96000 192000
        bits [0xe]: 16 20 24

It uses vendor id 0x10ec0257 and support for it was added into
snd-hda-codec-realtek in commit f429e7e494 which was introduced in
version v4.15.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f429e7e494afaded76e62c6f98211a635aa03098

I applied this patch to Debian's 4.9 kernel and mute & mic mute leds
started working. This one patch was enough.

Takashi, it is possible to backport this patch into -stable trees?

-- 
Pali Rohár
pali.rohar@gmail.com