On Thu, 27 Jun 2019 at 17:22, Jens Verwiebe info@jensverwiebe.de wrote:

Hi Nick

This looks like the same hurdle i once had with Helix.

Imho you should first try my patch to format.c and extend the vendor/model clause to your device:

diff --git a/sound/usb/format.c b/sound/usb/format.c index 2c44386..1c0107d 100644 --- a/sound/usb/format.c +++ b/sound/usb/format.c @@ -298,6 +298,20 @@ static int parse_audio_format_rates_v2(struct snd_usb_audio *chip, goto err; }

• /*
• • Line6 HELIX does not respond to sample rate
• • query requests. The only valid rate is 48000.
• */
• if (chip->usb_id == USB_ID(0x0e41, 0x4244)) {

•    fp->nr_rates = 1;
  

•        fp->rate_min = 48000;
  

•        fp->rate_max = 48000;
  

•        fp->rates = SNDRV_PCM_RATE_48000;
  

•        fp->rate_table = kmalloc(sizeof(int), GFP_KERNEL);
  

•        fp->rate_table[0] = 48000;
  

•        return 0;
  

•    }
  

• /* get the number of sample rates first by only fetching 2 bytes */
  ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
                USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
  
  

I can confirm that your patch get the device recognized in kernel 5.2 (I modfied it a bit). I'll work on this a bit and try to submit a patch to alsa to at least having the device available. Regarding the second part ( get_usb_high_speed_rate(rate + 5);) I think I have to debug it better because I don't think it can be accepted upstream. (maybe someone from the mailing list can help?)

I personally encountered still slight pops from time to time which i "healed" with an ugly second patch:

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index c90607e..026095a 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -878,6 +878,8 @@ int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,

  if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
      ep->freqn = get_usb_full_speed_rate(rate);

• else if (USB_ID(0x0e41, 0x4244))

•    ep->freqn = get_usb_high_speed_rate(rate + 5); // ugly helix hack
  else
      ep->freqn = get_usb_high_speed_rate(rate);
  
  
  

I still never could get the Line6 device to really follow the syncadaption in 16.16 format.

I tried all kinda voodoo like endpoint redirection ( like axe fx needs ) to no avail. Perhaps you have better ideas.

I would be very interested in getting Line6 devices usb-compliant mode working 100 % reliable.

The dream would be to have all samplerates. Btw:: i have sniffed data from Helix connected to a windows machine,

ioreg data from helix connected to an OSX(macOS) machine and even a bit experimented with retdec on the windows drivers ;).

This for now, 'am just on the jump to the Hamburg Linux Group :)

Lets stay in contact about this stuff.

Cheers ... Jens

Am 27.06.19 um 09:45 schrieb nick83ola:

...

Hi all, I just purchased an HX stomp and when I connect to linux I get the following error message:

 [  322.404503] usb 1-6: new high-speed USB device number 13 using xhci_hcd
 [  322.531804] usb 1-6: New USB device found, idVendor=0e41,

idProduct=4246, bcdDevice= 2.00 [ 322.531806] usb 1-6: New USB device strings: Mfr=1, Product=3, SerialNumber=2 [ 322.531806] usb 1-6: Product: HX Stomp [ 322.531807] usb 1-6: Manufacturer: LINE 6 [ 322.531808] usb 1-6: SerialNumber: 3021888 [ 322.535789] usb 1-6: parse_audio_format_rates_v2v3(): unable to retrieve number of sample rates (clock 16) [ 322.535907] usb 1-6: parse_audio_format_rates_v2v3(): unable to retrieve number of sample rates (clock 16)

I have some kernel development experience but not a lot with usb so can someone point me where to start looking?

there was a previous discussion on the mailing list related to this by Jens Verwiebe (and other request for help). Here are the relevant patches/discussion

 https://www.spinics.net/lists/alsa-devel/msg71459.html
 https://patchwork.kernel.org/patch/10113121/

If someone can help me I have an HX stomp here and time to do some debugging.

Also if someone from Line6 is listening would be helpful to have some hints.

Cheers Nicola Lunghi

--

Jens Verwiebe