linux-kernel - Re: [PATCH] ALSA: usb-audio: allow -EPIPE errors for some v2 messages

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Date:   Thu, 14 Oct 2021 12:56:26 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Takashi Iwai <tiwai@...e.de>
Cc:     Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
        alsa-devel@...a-project.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ALSA: usb-audio: allow -EPIPE errors for some v2 messages

On Tue, Oct 12, 2021 at 03:24:04PM +0200, Takashi Iwai wrote:
> On Tue, 12 Oct 2021 14:41:44 +0200,
> Greg Kroah-Hartman wrote:
> > 
> > On Tue, Oct 12, 2021 at 09:35:16AM +0200, Takashi Iwai wrote:
> > > On Mon, 11 Oct 2021 19:23:05 +0200,
> > > Greg Kroah-Hartman wrote:
> > > > 
> > > > On Mon, Oct 11, 2021 at 06:07:01PM +0200, Takashi Iwai wrote:
> > > > > Could you also post the contents of /proc/asound/card*/usbmixer (only
> > > > > for the corresponding device), too?
> > > > 
> > > > Sure, here it is:
> > > > 
> > > > USB Mixer: usb_id=0x30be0101, ctrlif=0, ctlerr=0
> > > > Card: Schiit Audio Schiit Hel at usb-0000:47:00.1-2.2, high speed
> > > >   Unit: 5
> > > >     Control: name="Mic - Input Jack", index=0
> > > >     Info: id=5, control=2, cmask=0x0, channels=1, type="BOOLEAN"
> > > >     Volume: min=0, max=1, dBmin=0, dBmax=0
> > > >   Unit: 7
> > > >     Control: name="Speaker - Output Jack", index=0
> > > >     Info: id=7, control=2, cmask=0x0, channels=1, type="BOOLEAN"
> > > >     Volume: min=0, max=1, dBmin=0, dBmax=0
> > > >   Unit: 13
> > > >     Control: name="PCM Playback Switch", index=0
> > > >     Info: id=13, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN"
> > > >     Volume: min=0, max=1, dBmin=0, dBmax=0
> > > >   Unit: 17
> > > >     Control: name="Mic Capture Switch", index=0
> > > >     Info: id=17, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN"
> > > >     Volume: min=0, max=1, dBmin=0, dBmax=0
> > > >   Unit: 18
> > > >     Control: name="Clock Source 18 Validity", index=0
> > > >     Info: id=18, control=2, cmask=0x0, channels=1, type="BOOLEAN"
> > > >     Volume: min=0, max=1, dBmin=0, dBmax=0
> > > >   Unit: 22
> > > >     Control: name="Clock Source 22 Validity", index=0
> > > >     Info: id=22, control=2, cmask=0x0, channels=1, type="BOOLEAN"
> > > >     Volume: min=0, max=1, dBmin=0, dBmax=0
> > > 
> > > Hm, I expected more exotic control that failed, but it was Mic Capture
> > > Switch, which should be treated normally.
> > > 
> > > Could you try the patch below?  This will still show other warning
> > > messages, but it'll forcibly initialize the mixer elements at probe
> > > time, and the rest should work.
> > > 
> > > Once after it's confirmed to work, we may shut up the device warnings
> > > with a quirk.
> > 
> > Only one warning message shows up, here's the dmesg with this patch
> > applied:
> > 
> > 
> > [Oct12 14:39] usb 7-2.2: new high-speed USB device number 10 using xhci_hcd
> > [  +0.123157] usb 7-2.2: New USB device found, idVendor=30be, idProduct=0101, bcdDevice= 1.02
> > [  +0.000009] usb 7-2.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> > [  +0.000003] usb 7-2.2: Product: Schiit Hel
> > [  +0.000002] usb 7-2.2: Manufacturer: Schiit Audio
> > [  +0.339785] usb 7-2.2: 17:0: failed to get current value for ch 0 (-32)
> > [  +0.020373] input: Schiit Audio Schiit Hel as /devices/pci0000:40/0000:40:01.1/0000:41:00.0/0000:42:08.0/0000:47:00.1/usb7/7-2/7-2.2/7-2.2:1.3/0003:30BE:0101.000B/input/input24
> > [  +0.056868] hid-generic 0003:30BE:0101.000B: input,hidraw6: USB HID v1.00 Device [Schiit Audio Schiit Hel] on usb-0000:47:00.1-2.2/input3
> 
> OK, then the problem is only about this unit and about the master
> channel.
> 
> > I don't see a "mic capture switch" on this device, but maybe it triggers
> > when I plug a mic into the microphone port, which is currently empty?
> 
> This should be persistent and visible; try to run "amixer -c1" (or the
> different card index for the device).
> 
> So far, so good.  The only remaining piece is how this -EPIPE error
> comes up.  Is this a protocol stall error or such?  Would it be
> avoided by adding the delay like done for some devices?
> 
> With the 5.15-rc kernel, you can pass quirk_flags option to
> snd-usb-audio module for applying known quirks.
> e.g. quirk_flags=0x100 will set the 1msec delay at each control
> message.  Please check whether it makes any difference.
> The option is an integer array for multiple devices, so if you have
> multiple USB-audio devices, put at the appropriate position in the
> array (e.g. quirk_flags=,,0x100 for the 3rd slot).

This quirk did not work.  Well, it caused the error to show up after a
delay, but the error is still there.

> The quirk bit 0x4000 will shut up the control errors.  If the above
> doesn't fix the warning and the device is working more or less, set
> this quirk to shut up the warning.  It can be set statically in the
> table at the end in sound/usb/quirks.c.

This quirk did work in that the error messages are still in the kernel
log, but the device seems to work properly now.

Let me send a patch that adds this device to the quirk table.

thanks for your help,

greg k-h