Hello,
I have the same issue with the device Focusrite Scarlett 8i6.
After investigating the source from the Kernel module
'snd_usb_audio' I found the issue and (partially) fixed it
on my system.
Since Kernel v6.12.115 there was a modification in the source
from the module, which result in this issue.
Linux-src/sound/usb/pcm.c:prepare_playback_urb():
v6.12.115:
for (i = 0; i < ctx->packets; i++) {
counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
if (counts < 0 || frames + counts >= ep->max_urb_frames)
break;
/* set up descriptor */
urb->iso_frame_desc[i].offset = frames * stride;
urb->iso_frame_desc[i].length = counts * stride;
It seems the 'if' logic isn't correct here, which cause the issue
on my system.
v6.12.113:
for (i = 0; i < ctx->packets; i++) {
counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
if (counts < 0)
break;
/* set up descriptor */
urb->iso_frame_desc[i].offset = frames * stride;
urb->iso_frame_desc[i].length = counts * stride;
This was the old code.
v7.4.x
for (i = 0; i < ctx->packets; i++) {
counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
if (counts < 0 ||
(frames + counts) * stride > ctx->buffer_size)
break;
/* set up descriptor */
urb->iso_frame_desc[i].offset = frames * stride;
urb->iso_frame_desc[i].length = counts * stride;
I used the code from Kernel v7.4.x in this module, which fixes
the issue for me.
Hope this help.
--
Kind regards,
Johannes K.
