[PATCH] Fix mic sound on Jieli webcam

[Marco Giunta <giun7a@gmail.com>]

Hi,
recently I've bought a usb webcam with integrated mic:

  Jieli Technology USB PHY 2.0 (1224:2a25)

The video part works well, but the mic sound is speedups, "like
minions" (cit.). When I connect the camera, these are the dmesg
messages:

kernel: usb 1-8: current rate 0 is different from the runtime rate 8000
kernel: usb 1-8: current rate 0 is different from the runtime rate 16000
kernel: usb 1-8: current rate 0 is different from the runtime rate 44100
kernel: usb 1-8: current rate 0 is different from the runtime rate 48000
kernel: usb 1-8: Warning! Unlikely big volume range (=4096), cval->res
is probably wrong.
kernel: usb 1-8: [3] FU [Mic Capture Volume] ch = 1, val = 0/4096/1
kernel: usbcore: registered new interface driver snd-usb-audio

and after a while, dmesg log is filled, every 5 seconds, with:

kernel: retire_capture_urb: 84 callbacks suppressed
kernel: retire_capture_urb: 1714 callbacks suppressed

A guy reports on ArchLinux bug website the same problem
(https://bugs.archlinux.org/task/68141?opened=12995&status%5B0%5D=)
and provides a patch to fix the sound issue. I've applied the patch on
kernel 5.9.13 (Fedora 33 x86_64) and now the mic works, no more
minions voice effect. Now dmesg messages are only:

kernel: usb 1-8: Warning! Unlikely big volume range (=4096), cval->res
is probably wrong.
kernel: usb 1-8: [3] FU [Mic Capture Volume] ch = 1, val = 0/4096/1
kernel: usbcore: registered new interface driver snd-usb-audio

the retire_capture_urb messages are gone.

All credits for the patch go to him but I don't know how to contact
that guy nor I don't know if he has already contacted you, so my
question is if you could review his patch and finally apply upstream.

If you need other information or you need a tester, I'm here.

Thanks,
  Marco

--- a/sound/usb/format.c    2020-10-01 18:36:35.000000000 +0300
+++ b/sound/usb/format.c    2020-10-04 02:10:21.678685952 +0300
@@ -217,6 +217,21 @@
                 (chip->usb_id == USB_ID(0x041e, 0x4064) ||
                  chip->usb_id == USB_ID(0x041e, 0x4068)))
                 rate = 8000;
+
+            // hack for "Jieli Technology USB PHY 2.0" webcam
+            if (chip->usb_id == USB_ID(0x1224, 0x2a25)) {
+                switch (rate) {
+                case 8000:
+                    fp->datainterval += 4;
+                    break;
+                case 16000:
+                    fp->datainterval += 3;
+                    break;
+                default:
+                    fp->datainterval += 1;
+                    break;
+                }
+            }

             fp->rate_table[fp->nr_rates] = rate;
             if (!fp->rate_min || rate < fp->rate_min)
--- a/sound/usb/endpoint.c    2020-10-01 18:36:35.000000000 +0300
+++ b/sound/usb/endpoint.c    2020-10-04 02:09:09.471978982 +0300
@@ -882,6 +882,8 @@
     if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) {
         packs_per_ms = 8 >> ep->datainterval;
         max_packs_per_urb = MAX_PACKS_HS;
+        if (!packs_per_ms)
+            packs_per_ms = 1;
     } else {
         packs_per_ms = 1;
         max_packs_per_urb = MAX_PACKS;
--- a/sound/usb/quirks.c    2020-10-01 18:36:35.000000000 +0300
+++ b/sound/usb/quirks.c    2020-10-04 02:14:04.532196519 +0300
@@ -1516,6 +1516,7 @@
     case USB_ID(0x1901, 0x0191): /* GE B850V3 CP2114 audio interface */
     case USB_ID(0x21b4, 0x0081): /* AudioQuest DragonFly */
     case USB_ID(0x2912, 0x30c8): /* Audioengine D1 */
+    case USB_ID(0x1224, 0x2a25): /* Jieli Technology USB PHY 2.0 */
         return true;
     }