* 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) -- links below jump to the message on this page -- 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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