Re: ThinkPad T480s & LED_MUTE, LED_MICMUTE

[Takashi Iwai]

On Tue, 19 Jun 2018 10:37:12 +0200,
Pali RohÃr wrote:
> 
> On Monday 18 June 2018 13:21:21 Pali RohÃr wrote:
> > On Monday 18 June 2018 12:36:31 Takashi Iwai wrote:
> > > On Mon, 18 Jun 2018 12:28:06 +0200,
> > > Pali RohÃr wrote:
> > > > 
> > > > On Saturday 16 June 2018 18:02:14 Takashi Iwai wrote:
> > > > > On Sat, 16 Jun 2018 17:43:09 +0200,
> > > > > Pali RohÃr wrote:
> > > > > > 
> > > > > > On Saturday 16 June 2018 09:05:41 Takashi Iwai wrote:
> > > > > > > On Fri, 15 Jun 2018 21:09:59 +0200,
> > > > > > > Pali RohÃr wrote:
> > > > > > > > 
> > > > > > > > On Friday 15 June 2018 14:51:47 Takashi Iwai wrote:
> > > > > > > > > On Fri, 08 Jun 2018 13:10:57 +0200,
> > > > > > > > > Pali RohÃr 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?

It has already a Cc-to-stable, so it should have been backported.
Maybe it wasn't applicable at that time due to lack of other dependent
patches...

In anyway, feel free to ping Greg for including it to 4.9.x if it
works for you now.


Takashi