Re: [PATCH] ALSA: usb-audio: Rate-limit URB submission error at stream start

[Takashi Iwai <tiwai@suse.de>]

On Mon, 26 Oct 2026 00:18:49 +0100,
Denis Kulikov wrote:
> 
> When two USB audio devices share a USB 2.0 hub (here a headset and a
> microphone), there may not be enough isochronous bandwidth to start the
> second stream, and usb_submit_urb() fails with -ENOSPC. PipeWire keeps
> retrying to start the stream every ~20 ms, and every attempt logs
> 
>   usb 2-1.1: cannot submit urb 0, error -28: not enough bandwidth
> 
> On my desktop this was printed up to 94 times per second and flooded
> the kernel log.
> 
> Use usb_audio_err_ratelimited() for this message, as commit
> 2db2be5607c4 ("ALSA: usb-audio: Rate limit usb_set_interface error
> reporting") already did for a neighbouring message in the same file.
> 
> Tested on that desktop (X79, Linux 7.3) with the headset and the
> microphone on one hub, starting playback and capture on both for 20
> seconds: the stock snd-usb-audio module printed the message 580 times,
> the patched one printed it 50 times and suppressed the rest.
> 
> Signed-off-by: Denis Kulikov <dar1knessx@gmail.com>

Applied now.  Thanks.


Takashi