Re: [PATCH 0/2] ALSA: usb-audio: Add quirks for HP Elite x3 Lap Dock

[Takashi Iwai <tiwai@suse.de>]

On Mon, 07 Sep 2026 21:34:38 +0200,
Rong Zhang wrote:
> 
> The HP Elite x3 Lap Dock is a laptop-like external display device with a
> FHD screen, a keyboard, and a MT touchpad. It can be connected via USB-C
> or Miracast. As an e-waste collector, I recently brought one for 69 CNY
> (10.2 USD). The price already indicates how broken the device's design
> and compatibility are ;-P
> 
> When connecting via USB-C, the video source is, of course, DisplayPort
> Alternate Mode. However, the audio source has nothing to do with the
> DisplayPort signal and is actually from a builtin UAC device.
> 
> The builtin UAC device provides three Alternate Settings:
> 
> - 1:1 - Capture, S16_LE, 8000/32000/44100/48000Hz
> - 2:1 - Playback, S16_LE, 48000Hz
> - 2:2 - Playback, S24_3LE, 48000Hz
> 
> Unfortunately, the last one is broken because:
> 
> - it doesn't accept SET_CUR(SAMPLE_RATE). QUIRK_FLAG_FIXED_RATE works
>   around it, however...
> - it constantly produces severe harmonic distortion once the capture
>   stream is also opened. The interface 2 must be closed and reopened to
>   make it recover. IOW, simply closing the capture stream makes no
>   difference.
> 
> Considering that S24_3LE offers no additional benefit on small speakers
> compared to S16_LE, and 2:1 is always usable as an alternative, skip 2:2
> to get rid of the trouble.
> 
> Setting chip->setup to any non-default value disables the fixup and
> reenables 2:2 (in this case QUIRK_FLAG_FIXED_RATE is required).
> 
> Quirky device sample:
> 
>   usb 7-1.4: new full-speed USB device number 50 using xhci_hcd
>   usb 7-1.4: New USB device found, idVendor=03f0, idProduct=0c56, bcdDevice= 0.00
>   usb 7-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
>   usb 7-1.4: Product: HP Elite x3 Lap Dock
>   usb 7-1.4: Manufacturer: HP
>   usb 7-1.4: Found last interface = 0
>   usb 7-1.4: 1:1: add audio endpoint 0x81
>   usb 7-1.4: Creating new data endpoint #81
>   usb 7-1.4: 1:1 Set sample rate 48000, clock 0
>   usb 7-1.4: 2:1: add audio endpoint 0x1
>   usb 7-1.4: Creating new data endpoint #1
>   usb 7-1.4: 2:1 Set sample rate 48000, clock 0
>   usb 7-1.4: 2:2: add audio endpoint 0x1
>   usb 7-1.4: 2:2 Set sample rate 48000, clock 0
>   usb 7-1.4: 2:2: cannot set freq 48000 to ep 0x1
>   usb 7-1.4: [9] FU [Sidetone Playback Switch] ch = 1, val = 0/1/1
>   usb 7-1.4: cannot set ctl value: req = 0x4, wValue = 0x200, wIndex = 0x900, type = 4, data = 0x40/0x0
>   usb 7-1.4: [9] FU [Sidetone Playback Volume] ch = 1, val = -17664/0/128
>   usb 7-1.4: [2] FU [Headset Playback Switch] ch = 1, val = 0/1/1
>   usb 7-1.4: [2] FU [Headset Playback Volume] ch = 2, val = -18944/0/1
>   usb 7-1.4: [6] FU [Headset Capture Switch] ch = 1, val = 0/1/1
>   usb 7-1.4: [6] FU [Headset Capture Volume] ch = 2, val = -18944/0/1
>   input: HP HP Elite x3 Lap Dock Consumer Control as /devices/pci0000:00/0000:00:08.3/0000:c9:00.4/usb7/7-1/7-1.4/7-1.4:1.3/0003:03F0:0C56.0033/input/input129
>   input: HP HP Elite x3 Lap Dock as /devices/pci0000:00/0000:00:08.3/0000:c9:00.4/usb7/7-1/7-1.4/7-1.4:1.3/0003:03F0:0C56.0033/input/input130
>   hid-generic 0003:03F0:0C56.0033: input,hiddev100,hidraw8: USB HID v1.11 Device [HP HP Elite x3 Lap Dock] on usb-0000:c9:00.4-1.4/input3
> 
> Signed-off-by: Rong Zhang <i@rong.moe>
> ---
> Rong Zhang (2):
>       ALSA: usb-audio: Convert snd_usb_apply_interface_quirk() into a switch statement
>       ALSA: usb-audio: Add quirks for HP Elite x3 Lap Dock

Applied both to for-next branch.  Thanks.


Takashi