Re: [alsa-devel] Exposing the ThinkPad HW mute switch to ALSA?
At Tue, 23 Sep 2014 19:16:52 -0700, Andy Lutomirski wrote:
ThinkPads have an extra mute switch that's controlled by the embedded controller. There are some hardware buttons associated with it.
We (thinkpad-acpi) can be notified about state changes in the mute switch, we can see presses of the hardware buttons and program them to send KEY_MUTE or not as appropriate, and we can (optionally) change the HW mute state.
However, I have no clue how to correctly expose the mute switch through ALSA so that userspace will know what it controls. It currently shows up as its own sound card, which is ridiculous.
Can anyone give me any hints as to how to expose this bonus audio control in a sensible manner? I know essentially nothing about ALSA.
(Some older ThinkPads also have a hardware volume control with similar behavior.)
It's a bit difficult issue, since this needs the weak module dependency. And even worse, different sound drivers might be used for a single thinkpad_acpi. So, from the programming POV, the individual sound card instance is the easiest approach.
Though, some HD-audio codec drivers already have a weak binding of thinkpad_acpi stuff for Mic-mute switch. I guess we can move the handling of the master mute switch to the sound driver as well.
If doing so, each relevant sound driver needs to implement it. IIRC, snd-intel8x0 is used on old Thinkpads. Any others?
Takashi
On Mon, 06 Oct 2014, Takashi Iwai wrote:
ThinkPads have an extra mute switch that's controlled by the embedded controller. There are some hardware buttons associated with it.
We (thinkpad-acpi) can be notified about state changes in the mute switch, we can see presses of the hardware buttons and program them to send KEY_MUTE or not as appropriate, and we can (optionally) change the HW mute state.
However, I have no clue how to correctly expose the mute switch through ALSA so that userspace will know what it controls. It currently shows up as its own sound card, which is ridiculous.
Can anyone give me any hints as to how to expose this bonus audio control in a sensible manner? I know essentially nothing about ALSA.
(Some older ThinkPads also have a hardware volume control with similar behavior.)
It's a bit difficult issue, since this needs the weak module dependency. And even worse, different sound drivers might be used for a single thinkpad_acpi. So, from the programming POV, the individual sound card instance is the easiest approach.
Though, some HD-audio codec drivers already have a weak binding of thinkpad_acpi stuff for Mic-mute switch. I guess we can move the handling of the master mute switch to the sound driver as well.
If doing so, each relevant sound driver needs to implement it. IIRC, snd-intel8x0 is used on old Thinkpads. Any others?
As far as I know, all old ones use the snd-intel8x0 AC97 hba, but several different codecs behind that.
On Mon, Oct 6, 2014 at 12:09 PM, Henrique de Moraes Holschuh hmh@hmh.eng.br wrote:
On Mon, 06 Oct 2014, Takashi Iwai wrote:
ThinkPads have an extra mute switch that's controlled by the embedded controller. There are some hardware buttons associated with it.
We (thinkpad-acpi) can be notified about state changes in the mute switch, we can see presses of the hardware buttons and program them to send KEY_MUTE or not as appropriate, and we can (optionally) change the HW mute state.
However, I have no clue how to correctly expose the mute switch through ALSA so that userspace will know what it controls. It currently shows up as its own sound card, which is ridiculous.
Can anyone give me any hints as to how to expose this bonus audio control in a sensible manner? I know essentially nothing about ALSA.
(Some older ThinkPads also have a hardware volume control with similar behavior.)
It's a bit difficult issue, since this needs the weak module dependency. And even worse, different sound drivers might be used for a single thinkpad_acpi. So, from the programming POV, the individual sound card instance is the easiest approach.
Though, some HD-audio codec drivers already have a weak binding of thinkpad_acpi stuff for Mic-mute switch. I guess we can move the handling of the master mute switch to the sound driver as well.
If doing so, each relevant sound driver needs to implement it. IIRC, snd-intel8x0 is used on old Thinkpads. Any others?
As far as I know, all old ones use the snd-intel8x0 AC97 hba, but several different codecs behind that.
FWIW, I don't know whether any of the pre-hda thinkpads have the ACPI HAUM/SAUM mechanism, so I have no idea how good our support for the hardware mute switch and controls will ever be on those laptops.
--Andy
-- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh
At Mon, 6 Oct 2014 17:06:19 -0700, Andy Lutomirski wrote:
On Mon, Oct 6, 2014 at 12:09 PM, Henrique de Moraes Holschuh hmh@hmh.eng.br wrote:
On Mon, 06 Oct 2014, Takashi Iwai wrote:
ThinkPads have an extra mute switch that's controlled by the embedded controller. There are some hardware buttons associated with it.
We (thinkpad-acpi) can be notified about state changes in the mute switch, we can see presses of the hardware buttons and program them to send KEY_MUTE or not as appropriate, and we can (optionally) change the HW mute state.
However, I have no clue how to correctly expose the mute switch through ALSA so that userspace will know what it controls. It currently shows up as its own sound card, which is ridiculous.
Can anyone give me any hints as to how to expose this bonus audio control in a sensible manner? I know essentially nothing about ALSA.
(Some older ThinkPads also have a hardware volume control with similar behavior.)
It's a bit difficult issue, since this needs the weak module dependency. And even worse, different sound drivers might be used for a single thinkpad_acpi. So, from the programming POV, the individual sound card instance is the easiest approach.
Though, some HD-audio codec drivers already have a weak binding of thinkpad_acpi stuff for Mic-mute switch. I guess we can move the handling of the master mute switch to the sound driver as well.
If doing so, each relevant sound driver needs to implement it. IIRC, snd-intel8x0 is used on old Thinkpads. Any others?
As far as I know, all old ones use the snd-intel8x0 AC97 hba, but several different codecs behind that.
FWIW, I don't know whether any of the pre-hda thinkpads have the ACPI HAUM/SAUM mechanism, so I have no idea how good our support for the hardware mute switch and controls will ever be on those laptops.
IIRC, they have, and the mute worked completely independently from the onboard sound controller. But my memory is pretty vague.
Takashi
so I have a really dumb question.
Why can't the controls be mapped as HCI rather than a soundcard? given there's no audio production capability here only a control capability.
Also this seems to be how they end up functioning on a modern system they get bound to pulse which remaps them to whatever's 'active'
Why does everyone say that this is a soundcard when it's really a keyboard (from my pov)
also what's the least surprise here?
Should this control control volume of my BT headset when it's active (It currently does which I find convenient but I can see an argument that it's surprising and should be bound to the phys hardware on the laptop)
On Tue, Oct 7, 2014 at 4:25 PM, Takashi Iwai tiwai@suse.de wrote:
At Mon, 6 Oct 2014 17:06:19 -0700, Andy Lutomirski wrote:
On Mon, Oct 6, 2014 at 12:09 PM, Henrique de Moraes Holschuh hmh@hmh.eng.br wrote:
On Mon, 06 Oct 2014, Takashi Iwai wrote:
ThinkPads have an extra mute switch that's controlled by the
embedded
controller. There are some hardware buttons associated with it.
We (thinkpad-acpi) can be notified about state changes in the mute switch, we can see presses of the hardware buttons and program them
to
send KEY_MUTE or not as appropriate, and we can (optionally) change the HW mute state.
However, I have no clue how to correctly expose the mute switch through ALSA so that userspace will know what it controls. It currently shows up as its own sound card, which is ridiculous.
Can anyone give me any hints as to how to expose this bonus audio control in a sensible manner? I know essentially nothing about
ALSA.
(Some older ThinkPads also have a hardware volume control with
similar
behavior.)
It's a bit difficult issue, since this needs the weak module dependency. And even worse, different sound drivers might be used for a single thinkpad_acpi. So, from the programming POV, the individual sound card instance is the easiest approach.
Though, some HD-audio codec drivers already have a weak binding of thinkpad_acpi stuff for Mic-mute switch. I guess we can move the handling of the master mute switch to the sound driver as well.
If doing so, each relevant sound driver needs to implement it. IIRC, snd-intel8x0 is used on old Thinkpads. Any others?
As far as I know, all old ones use the snd-intel8x0 AC97 hba, but
several
different codecs behind that.
FWIW, I don't know whether any of the pre-hda thinkpads have the ACPI HAUM/SAUM mechanism, so I have no idea how good our support for the hardware mute switch and controls will ever be on those laptops.
IIRC, they have, and the mute worked completely independently from the onboard sound controller. But my memory is pretty vague.
Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
At Tue, 7 Oct 2014 17:25:13 +1100, Grant Diffey wrote:
so I have a really dumb question.
Why can't the controls be mapped as HCI rather than a soundcard? given there's no audio production capability here only a control capability.
Also this seems to be how they end up functioning on a modern system they get bound to pulse which remaps them to whatever's 'active'
Why does everyone say that this is a soundcard when it's really a keyboard (from my pov)
thinkpad_acpi actually mutes the sound on some models, at least the old ones, independently from the sound chip mute state. That's why it was implemented as the sound card object initially.
Takashi
On Tue, 07 Oct 2014, Takashi Iwai wrote:
At Tue, 7 Oct 2014 17:25:13 +1100, Grant Diffey wrote:
so I have a really dumb question.
Why can't the controls be mapped as HCI rather than a soundcard? given there's no audio production capability here only a control capability.
Also this seems to be how they end up functioning on a modern system they get bound to pulse which remaps them to whatever's 'active'
Why does everyone say that this is a soundcard when it's really a keyboard (from my pov)
thinkpad_acpi actually mutes the sound on some models, at least the old ones, independently from the sound chip mute state. That's why it was implemented as the sound card object initially.
That's how the hardware works, really. One AC97 audio channel is routed to a digital volume chip, and from there to the console headphone jack, and to the built-in speakers. line-out is not routed through this chip, and AFAIK MIC/line-in is not routed through either this chip _or_ a separate mute gate, either.
The EC controls this digital volume chip directly, it is independent from the AC97 mixer. The default behaviour cannot be changed in earlier thinkpads, and trying to change it in later thinkpads (they're supposed to have a legacy mode that is the same as the older models) doesn't work very well.
Line-out and MIC are controlled only by the AC97 mixer in the older models with digital volume control.
In newer-but-not-newest thinkpads, there are two mute gates, one for MIC, and another for the speakers/headphones. The EC controls those. All volume control is in the HDA mixer.
In the newest thinkpads, I think there's only a MIC mute gate controlled by the EC, and everything else is in the HDA mixer.
And depeding on the EC operating mode and thinkpad model, the volume hotkeys might interact with the mute state (unmuting on first press when it is mute).
On Oct 7, 2014 6:20 AM, "Henrique de Moraes Holschuh" hmh@hmh.eng.br wrote:
On Tue, 07 Oct 2014, Takashi Iwai wrote:
At Tue, 7 Oct 2014 17:25:13 +1100, Grant Diffey wrote:
so I have a really dumb question.
Why can't the controls be mapped as HCI rather than a soundcard? given there's no audio production capability here only a control capability.
Also this seems to be how they end up functioning on a modern system they get bound to pulse which remaps them to whatever's 'active'
Why does everyone say that this is a soundcard when it's really a keyboard (from my pov)
thinkpad_acpi actually mutes the sound on some models, at least the old ones, independently from the sound chip mute state. That's why it was implemented as the sound card object initially.
That's how the hardware works, really. One AC97 audio channel is routed to a digital volume chip, and from there to the console headphone jack, and to the built-in speakers. line-out is not routed through this chip, and AFAIK MIC/line-in is not routed through either this chip _or_ a separate mute gate, either.
The EC controls this digital volume chip directly, it is independent from the AC97 mixer. The default behaviour cannot be changed in earlier thinkpads, and trying to change it in later thinkpads (they're supposed to have a legacy mode that is the same as the older models) doesn't work very well.
Line-out and MIC are controlled only by the AC97 mixer in the older models with digital volume control.
In newer-but-not-newest thinkpads, there are two mute gates, one for MIC, and another for the speakers/headphones. The EC controls those. All volume control is in the HDA mixer.
In the newest thinkpads, I think there's only a MIC mute gate controlled by the EC, and everything else is in the HDA mixer.
And depeding on the EC operating mode and thinkpad model, the volume hotkeys might interact with the mute state (unmuting on first press when it is mute).
On newish thinkpads (at least X60-X220, and I think this works on the latest models as well), we can disable all of this and make the mute button be a regular button if we want. Getting the mute LED to DTRT might be tricky, but modern userspace can probably do it.
This is almost certainly the approach that does something sensible with the least code written. We would just check for HAUM/SAUM on startup and, if available, set SAUM to "software control only", force-unmute the mute circuit, force the volume to full, and disable the fake soundcard.
--Andy
-- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh
At Tue, 7 Oct 2014 07:44:35 -0700, Andy Lutomirski wrote:
On Oct 7, 2014 6:20 AM, "Henrique de Moraes Holschuh" hmh@hmh.eng.br wrote:
On Tue, 07 Oct 2014, Takashi Iwai wrote:
At Tue, 7 Oct 2014 17:25:13 +1100, Grant Diffey wrote:
so I have a really dumb question.
Why can't the controls be mapped as HCI rather than a soundcard? given there's no audio production capability here only a control capability.
Also this seems to be how they end up functioning on a modern system they get bound to pulse which remaps them to whatever's 'active'
Why does everyone say that this is a soundcard when it's really a keyboard (from my pov)
thinkpad_acpi actually mutes the sound on some models, at least the old ones, independently from the sound chip mute state. That's why it was implemented as the sound card object initially.
That's how the hardware works, really. One AC97 audio channel is routed to a digital volume chip, and from there to the console headphone jack, and to the built-in speakers. line-out is not routed through this chip, and AFAIK MIC/line-in is not routed through either this chip _or_ a separate mute gate, either.
The EC controls this digital volume chip directly, it is independent from the AC97 mixer. The default behaviour cannot be changed in earlier thinkpads, and trying to change it in later thinkpads (they're supposed to have a legacy mode that is the same as the older models) doesn't work very well.
Line-out and MIC are controlled only by the AC97 mixer in the older models with digital volume control.
In newer-but-not-newest thinkpads, there are two mute gates, one for MIC, and another for the speakers/headphones. The EC controls those. All volume control is in the HDA mixer.
In the newest thinkpads, I think there's only a MIC mute gate controlled by the EC, and everything else is in the HDA mixer.
And depeding on the EC operating mode and thinkpad model, the volume hotkeys might interact with the mute state (unmuting on first press when it is mute).
On newish thinkpads (at least X60-X220, and I think this works on the latest models as well), we can disable all of this and make the mute button be a regular button if we want. Getting the mute LED to DTRT might be tricky, but modern userspace can probably do it.
This is almost certainly the approach that does something sensible with the least code written. We would just check for HAUM/SAUM on startup and, if available, set SAUM to "software control only", force-unmute the mute circuit, force the volume to full, and disable the fake soundcard.
That sounds sensible. But, we'll still need to handle the mute LED, like we do for the mic-mute LED now?
Takashi
On Tue, Oct 7, 2014 at 7:50 AM, Takashi Iwai tiwai@suse.de wrote:
At Tue, 7 Oct 2014 07:44:35 -0700, Andy Lutomirski wrote:
On Oct 7, 2014 6:20 AM, "Henrique de Moraes Holschuh" hmh@hmh.eng.br wrote:
On Tue, 07 Oct 2014, Takashi Iwai wrote:
At Tue, 7 Oct 2014 17:25:13 +1100, Grant Diffey wrote:
so I have a really dumb question.
Why can't the controls be mapped as HCI rather than a soundcard? given there's no audio production capability here only a control capability.
Also this seems to be how they end up functioning on a modern system they get bound to pulse which remaps them to whatever's 'active'
Why does everyone say that this is a soundcard when it's really a keyboard (from my pov)
thinkpad_acpi actually mutes the sound on some models, at least the old ones, independently from the sound chip mute state. That's why it was implemented as the sound card object initially.
That's how the hardware works, really. One AC97 audio channel is routed to a digital volume chip, and from there to the console headphone jack, and to the built-in speakers. line-out is not routed through this chip, and AFAIK MIC/line-in is not routed through either this chip _or_ a separate mute gate, either.
The EC controls this digital volume chip directly, it is independent from the AC97 mixer. The default behaviour cannot be changed in earlier thinkpads, and trying to change it in later thinkpads (they're supposed to have a legacy mode that is the same as the older models) doesn't work very well.
Line-out and MIC are controlled only by the AC97 mixer in the older models with digital volume control.
In newer-but-not-newest thinkpads, there are two mute gates, one for MIC, and another for the speakers/headphones. The EC controls those. All volume control is in the HDA mixer.
In the newest thinkpads, I think there's only a MIC mute gate controlled by the EC, and everything else is in the HDA mixer.
And depeding on the EC operating mode and thinkpad model, the volume hotkeys might interact with the mute state (unmuting on first press when it is mute).
On newish thinkpads (at least X60-X220, and I think this works on the latest models as well), we can disable all of this and make the mute button be a regular button if we want. Getting the mute LED to DTRT might be tricky, but modern userspace can probably do it.
This is almost certainly the approach that does something sensible with the least code written. We would just check for HAUM/SAUM on startup and, if available, set SAUM to "software control only", force-unmute the mute circuit, force the volume to full, and disable the fake soundcard.
That sounds sensible. But, we'll still need to handle the mute LED, like we do for the mic-mute LED now?
Already done, I think:
if (led_set_func(TPACPI_LED_MUTE, false) >= 0) { old_vmaster_hook = spec->vmaster_mute.hook; spec->vmaster_mute.hook = update_tpacpi_mute_led; removefunc = false; }
Admittedly, I see some value in having the mute button mute things regardless of what userspace is doing, but I don't see *much* value in it. And, arguably, if that behavior is actually desirable, it should be available on all laptops, not just ThinkPads.
--Andy
At Tue, 7 Oct 2014 17:43:11 -0700, Andy Lutomirski wrote:
On Tue, Oct 7, 2014 at 7:50 AM, Takashi Iwai tiwai@suse.de wrote:
At Tue, 7 Oct 2014 07:44:35 -0700, Andy Lutomirski wrote:
On Oct 7, 2014 6:20 AM, "Henrique de Moraes Holschuh" hmh@hmh.eng.br wrote:
On Tue, 07 Oct 2014, Takashi Iwai wrote:
At Tue, 7 Oct 2014 17:25:13 +1100, Grant Diffey wrote:
so I have a really dumb question.
Why can't the controls be mapped as HCI rather than a soundcard? given there's no audio production capability here only a control capability.
Also this seems to be how they end up functioning on a modern system they get bound to pulse which remaps them to whatever's 'active'
Why does everyone say that this is a soundcard when it's really a keyboard (from my pov)
thinkpad_acpi actually mutes the sound on some models, at least the old ones, independently from the sound chip mute state. That's why it was implemented as the sound card object initially.
That's how the hardware works, really. One AC97 audio channel is routed to a digital volume chip, and from there to the console headphone jack, and to the built-in speakers. line-out is not routed through this chip, and AFAIK MIC/line-in is not routed through either this chip _or_ a separate mute gate, either.
The EC controls this digital volume chip directly, it is independent from the AC97 mixer. The default behaviour cannot be changed in earlier thinkpads, and trying to change it in later thinkpads (they're supposed to have a legacy mode that is the same as the older models) doesn't work very well.
Line-out and MIC are controlled only by the AC97 mixer in the older models with digital volume control.
In newer-but-not-newest thinkpads, there are two mute gates, one for MIC, and another for the speakers/headphones. The EC controls those. All volume control is in the HDA mixer.
In the newest thinkpads, I think there's only a MIC mute gate controlled by the EC, and everything else is in the HDA mixer.
And depeding on the EC operating mode and thinkpad model, the volume hotkeys might interact with the mute state (unmuting on first press when it is mute).
On newish thinkpads (at least X60-X220, and I think this works on the latest models as well), we can disable all of this and make the mute button be a regular button if we want. Getting the mute LED to DTRT might be tricky, but modern userspace can probably do it.
This is almost certainly the approach that does something sensible with the least code written. We would just check for HAUM/SAUM on startup and, if available, set SAUM to "software control only", force-unmute the mute circuit, force the volume to full, and disable the fake soundcard.
That sounds sensible. But, we'll still need to handle the mute LED, like we do for the mic-mute LED now?
Already done, I think:
if (led_set_func(TPACPI_LED_MUTE, false) >= 0) { old_vmaster_hook = spec->vmaster_mute.hook; spec->vmaster_mute.hook = update_tpacpi_mute_led; removefunc = false; }
Ah, right, I forgot that we have already both mute LEDs.
Admittedly, I see some value in having the mute button mute things regardless of what userspace is doing, but I don't see *much* value in it. And, arguably, if that behavior is actually desirable, it should be available on all laptops, not just ThinkPads.
Yes.
Takashi
On 2014-10-08 02:43, Andy Lutomirski wrote:
Admittedly, I see some value in having the mute button mute things regardless of what userspace is doing, but I don't see *much* value in it. And, arguably, if that behavior is actually desirable, it should be available on all laptops, not just ThinkPads.
Things start to get tricky when you think one step ahead and ask yourself what outputs the button and the LED really should control. We touched the topic briefly when discussing LEDs on the audio meeting last year. I'm attaching my presentation for reference.
(The outcome of the discussion about the mic mute LED was "we don't know, go ask designers", and well, you probably know the result, as we ended up with "The internal card's mics" for the mic mute LED.)
On Tue, 07 Oct 2014, Grant Diffey wrote:
so I have a really dumb question.
Why can't the controls be mapped as HCI rather than a soundcard? given there's no audio production capability here only a control capability.
Also this seems to be how they end up functioning on a modern system they get bound to pulse which remaps them to whatever's 'active'
FYI, on the old thinkpads it is the console audio volume control. It *only* affects the built-in speakers and the built-in headphone output. It does _not_ affect line-out. It does _not_ affect add-in soundcards. And it operates entirely inside the EC, with zero need of any OS assistance.
Those thinkpads don't have a separate MIC-mute button, though. I never tested them for mic-mute functionality come to think of it... the AC97 mixer in the soundcard can mute the mic, and I don't think there's an external MIC mute, because the chip they used for digital console volume control doesn't have mic channels.
Should this control control volume of my BT headset when it's active (It currently does which I find convenient but I can see an argument that it's surprising and should be bound to the phys hardware on the laptop)
Both alternatives are acceptable, as long as it doesn't lie. And on old thinkpads, you must take special action and not feed it back into the internal AC97 mixer, because it will _always_ control the console digital volume, it cannot be overriden in the older models, and the override doesn't work well because whomever wrote the EC code for the other operating modes did not test it properly.
BTW: old thinkpads don't use an ACPI interface to interact with the EC mixer, it is done by direct EC register access, and we whitelist the models where it works (the list is complete AFAIK).
participants (5)
-
Andy Lutomirski -
David Henningsson -
Grant Diffey -
Henrique de Moraes Holschuh -
Takashi Iwai