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Date:   Fri, 21 Apr 2023 15:48:27 +0100
From:   Chris Down <chris@chrisdown.name>
To:     Takashi Iwai <tiwai@suse.de>
Cc:     linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org,
        Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>
Subject: Re: [PATCH] usb-audio: Rate limit usb_set_interface error reporting
Message-ID: <ZEKiO7lh94QUyuAs@chrisdown.name>
References: <ZEKf8UYBYa1h4JWR@chrisdown.name>
 <87wn25qosu.wl-tiwai@suse.de>
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Hi Takashi,

Takashi Iwai writes:
>This patch itself is safe and good to have, so I'm going to take it as
>is.

Thanks!

>But I'm still curious in which code path the problem happens.  That
>is, we should address such unnecessary repeats if possible.  Do you
>have some more data?

Unfortunately not, I've been running with a kernel testing some other mm 
changes recently so haven't had a chance to debug what's going on here. But it 
starts like this:

     [Fri Apr 21 13:21:10 2023] usb 3-7: USB disconnect, device number 39
     [Fri Apr 21 13:21:10 2023] usb 3-7.1: USB disconnect, device number 40
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.1: USB disconnect, device number 42
     [Fri Apr 21 13:21:10 2023] usb 3-7.4: cannot submit urb (err = -19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.4: Unable to submit urb #2: -19 at snd_usb_queue_pending_output_urbs
     [Fri Apr 21 13:21:10 2023] usb 3-7.4: cannot submit urb 0, error -19: no device
     [Fri Apr 21 13:21:10 2023] usb 3-7.4: cannot submit urb 0, error -19: no device
     [Fri Apr 21 13:21:10 2023] usb 3-7.4: cannot submit urb 0, error -19: no device
     [Fri Apr 21 13:21:10 2023] usb 3-7.4: 1:0: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.4: 2:0: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.2: USB disconnect, device number 44
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.4: 1:1: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.4: 1:1: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.4: 1:1: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.4: 1:1: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.4: 1:1: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.4: 1:1: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.4: 1:1: usb_set_interface failed (-19)
     [Fri Apr 21 13:21:10 2023] usb 3-7.1.4: 1:1: usb_set_interface failed (-19)
     [... thousands of messages ensue ...]

So it looks like maybe some ordering is not quite right in destruction, perhaps 
only on multi-level USB topologies?

Thanks,

Chris