linux-kernel - Re: retire_capture_urb: Corrected urb data len

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Date:   Sun, 28 Aug 2022 09:49:35 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Sean Anderson <sean.anderson@...o.com>
Cc:     Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
        alsa-devel@...a-project.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: retire_capture_urb: Corrected urb data len

On Fri, 26 Aug 2022 20:57:53 +0200,
Sean Anderson wrote:
> 
> On 8/26/22 12:36 PM, Takashi Iwai wrote:
> > On Fri, 26 Aug 2022 18:22:24 +0200,
> > Sean Anderson wrote:
> >> 
> >> Hi all,
> >> 
> >> I have a "FiiO DigiHug USB Audio" sound card (1852:7022) [3]. I have had
> >> no problems with the audio, but I did notice a large number of message
> >> like 
> >> 
> >> retire_capture_urb: 4992 callbacks suppressed
> >> 
> >> in my dmesg [1]. This is caused by the "Corrected urb data len."
> >> warning.
> > 
> > What exact values are shown there?
> 
> Unfortunately, as detailed below, I was unable to turn off ratelimiting.
> 
> > The problem is that your hardware
> > (likely a buggy firmware) returns the unaligned size of bytes as the
> > data.  Maybe it's worth to replace dev_warn_ratelimited() there with
> > dev_warn() and take all warnings once.  Then we can see what kind of
> > values are delivered from the hardware.
> 
> I'll have an attempt at that next week
> 
> >> The patch adding this warning [2] makes it seem like
> >> this warning should be an uncommon occurance. However, based on the
> >> number of suppressed callbacks, this seems to be happening at a rate of
> >> around 500 Hz.
> >> 
> >> Is this buggy hardware? Or is this a bug in the driver? Does there need
> >> to be a quirk? Or perhaps the warning above should be a debug instead?
> > 
> > There is no quirk for that.  As long as the device works with that
> > workaround (except for messages), we can simply add a quirk to not
> > warn but always apply the workaround silently for such devices.
> 
> OK. I wasn't sure what the correct resolution would be.

Actually I was wrong: the existing quirk QUIRK_FLAG_ALIGN_TRANSFER
should cover that.

Could you try to pass quirk_flags=0x04 for the corresponding card slot
(the option takes an array) to snd-usb-audio module?  Alternatively,
try to pass quirk_alias=18557022:0e510408 to snd-usb-audio?


thanks,

Takashi