* How to annotate USB jacks without jack detection?
@ 2020-12-11 7:14 Kai-Heng Feng
2020-12-11 9:06 ` Takashi Iwai
0 siblings, 1 reply; 3+ messages in thread
From: Kai-Heng Feng @ 2020-12-11 7:14 UTC (permalink / raw)
To: SOUND
Hi,
There are some UAC1 devices come with jacks, but without jack detection
ability. And many USB/Thunderbolt docks are equipped with such USB
device.
Userspace like PulseAudio automatically switch to USB audio when they
gets plugged. However, auto-switching to UAC1 device can be problematic
because it may not connected to any headset or speaker.
So I wonder what's the best way to let userspace know the USB device is
a jack without jack detection ability? Through sysfs or dedicated UCM
conf?
Kai-Heng
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: How to annotate USB jacks without jack detection?
2020-12-11 7:14 How to annotate USB jacks without jack detection? Kai-Heng Feng
@ 2020-12-11 9:06 ` Takashi Iwai
2020-12-11 12:31 ` Kai-Heng Feng
0 siblings, 1 reply; 3+ messages in thread
From: Takashi Iwai @ 2020-12-11 9:06 UTC (permalink / raw)
To: Kai-Heng Feng; +Cc: SOUND
On Fri, 11 Dec 2020 08:14:24 +0100,
Kai-Heng Feng wrote:
>
> Hi,
>
> There are some UAC1 devices come with jacks, but without jack
> detection ability. And many USB/Thunderbolt docks are equipped with
> such USB device.
>
> Userspace like PulseAudio automatically switch to USB audio when they
> gets plugged. However, auto-switching to UAC1 device can be
> problematic because it may not connected to any headset or speaker.
>
> So I wonder what's the best way to let userspace know the USB device
> is a jack without jack detection ability? Through sysfs or dedicated
> UCM conf?
It's a good question. AFAIK, that's a long-standing problem, and most
of such devices provide the jack detection via HID, which is,
obviously, a completely different driver. So, if HID driver actually
creates input devices, we'd need to associate them with the sound card
somehow (likely in user-space). But I have no clear idea what's the
best approach yet.
Also, I'm not sure whether HID device really gives the right jack
detection event. A cheap UAC1 device I have here doesn't seem to give
the jack detection but only the mute/volume events, as it seems...
OTOH, there are some UAC2 devices providing the jack detection in the
USB-audio interface, and they seem work as is of now.
thanks,
Takashi
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: How to annotate USB jacks without jack detection?
2020-12-11 9:06 ` Takashi Iwai
@ 2020-12-11 12:31 ` Kai-Heng Feng
0 siblings, 0 replies; 3+ messages in thread
From: Kai-Heng Feng @ 2020-12-11 12:31 UTC (permalink / raw)
To: Takashi Iwai; +Cc: SOUND
On Fri, Dec 11, 2020 at 10:06, Takashi Iwai <tiwai@suse.de> wrote:
> On Fri, 11 Dec 2020 08:14:24 +0100,
> Kai-Heng Feng wrote:
>>
>> Hi,
>>
>> There are some UAC1 devices come with jacks, but without jack
>> detection ability. And many USB/Thunderbolt docks are equipped with
>> such USB device.
>>
>> Userspace like PulseAudio automatically switch to USB audio when
>> they
>> gets plugged. However, auto-switching to UAC1 device can be
>> problematic because it may not connected to any headset or speaker.
>>
>> So I wonder what's the best way to let userspace know the USB device
>> is a jack without jack detection ability? Through sysfs or dedicated
>> UCM conf?
>
> It's a good question. AFAIK, that's a long-standing problem, and most
> of such devices provide the jack detection via HID, which is,
> obviously, a completely different driver. So, if HID driver actually
> creates input devices, we'd need to associate them with the sound card
> somehow (likely in user-space). But I have no clear idea what's the
> best approach yet.
I didn't know that. Thanks for the info!
That explains the reason why HP TBT dock can do jack detection under
Windows, while it's just a UAC1 device.
>
> Also, I'm not sure whether HID device really gives the right jack
> detection event. A cheap UAC1 device I have here doesn't seem to give
> the jack detection but only the mute/volume events, as it seems...
For the HP TBT dock I can see a plug/unplug events, from its USB HID
interface.
>
> OTOH, there are some UAC2 devices providing the jack detection in the
> USB-audio interface, and they seem work as is of now.
Now I know the event is from its HID interface, let me see if I can
hook them together.
Kai-Heng
>
>
> thanks,
>
> Takashi
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-12-11 12:33 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2020-12-11 7:14 How to annotate USB jacks without jack detection? Kai-Heng Feng
2020-12-11 9:06 ` Takashi Iwai
2020-12-11 12:31 ` Kai-Heng Feng
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