[PATCH] Fix mic sound on Jieli webcam

[Takashi Iwai]

On Thu, 17 Dec 2020 14:24:58 +0100,
Marco Giunta wrote:
> 
> On Thu, Dec 17, 2020 at 1:17 PM Takashi Iwai <tiwai at suse.de> wrote:
> >
> > bInterval in the descriptor should show the value.
> > At best, give the output of lsusb -v for the device.
> 
> Here my lsusb:

Thanks.

>     Interface Association:
>       bLength                 8
>       bDescriptorType        11
>       bFirstInterface         2
>       bInterfaceCount         2
>       bFunctionClass          1 Audio
>       bFunctionSubClass       2 Streaming
>       bFunctionProtocol       0
>       iFunction               5 USB Microphone
>     Interface Descriptor:
(snip)
>       AudioStreaming Interface Descriptor:
>         bLength                11
>         bDescriptorType        36
>         bDescriptorSubtype      2 (FORMAT_TYPE)
>         bFormatType             1 (FORMAT_TYPE_I)
>         bNrChannels             1
>         bSubframeSize           2
>         bBitResolution         16
>         bSamFreqType            1 Discrete
>         tSamFreq[ 0]         8000
>       Endpoint Descriptor:
>         bLength                 9
>         bDescriptorType         5
>         bEndpointAddress     0x82  EP 2 IN
>         bmAttributes            1
>           Transfer Type            Isochronous
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0100  1x 256 bytes
>         bInterval               4

It's 4, and the same is set for all sample rates (8000, 16000, 44100,
48000).

If you don't tweak the datainterval, which error do you get?
The actual error message should appear before "... xx callbacks
suppressed" line.

BTW, the errors at the current sample rate checks could be better
avoided by treating the return value 0 specially, something like
below.


Takashi

-- 8< --
From: Takashi Iwai <tiwai at suse.de>
Subject: [PATCH] ALSA: usb-audio: Disable sample read check if firmware
 doesn't give back

Some buggy firmware don't give the current sample rate but leaves
zero.  Handle this case more gracefully without warning but just skip
the current rate verification from the next time.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/usb/clock.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index e940dcee792b..31051f2be46d 100644
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -534,6 +534,12 @@ static int set_sample_rate_v1(struct snd_usb_audio *chip,
 	}
 
 	crate = data[0] | (data[1] << 8) | (data[2] << 16);
+	if (!crate) {
+		dev_info(&dev->dev, "failed to read current rate; disabling the check\n");
+		chip->sample_rate_read_error = 3; /* three strikes, see above */
+		return 0;
+	}
+
 	if (crate != rate) {
 		dev_warn(&dev->dev, "current rate %d is different from the runtime rate %d\n", crate, rate);
 		// runtime->rate = crate;
-- 
2.26.2