Logitech C270 webcam floods the log

Logitech C270 webcam floods the log

[Jean Delvare]

Hi all,

When my Logitech C270 webcam is plugged in, my kernel log gets filled
with this message:

usb 3-4.1: reset high-speed USB device number 4 using xhci_hcd

every 5 seconds. I have the same problem on 3 different Intel-based
computers (different generations), using 2 different webcams, same
brand "same model".

Is Logitech doing crappy hardware these days, or are we doing something
wrong? Is there any way to know the reason that triggers the reset?

I would be more than happy to provide any relevant debugging
information if anyone is able to make it stop. As it stands, I must
plug my webcam before using it and unplug it as soon as I'm done, which
isn't exactly convenient.

Thanks,
-- 
Jean Delvare
SUSE L3 Support

Re: Logitech C270 webcam floods the log

[Laurent Pinchart]

Hi Jean,

On Wed, Oct 23, 2019 at 03:18:59PM +0200, Jean Delvare wrote:
> Hi all,
> 
> When my Logitech C270 webcam is plugged in, my kernel log gets filled
> with this message:
> 
> usb 3-4.1: reset high-speed USB device number 4 using xhci_hcd
> 
> every 5 seconds. I have the same problem on 3 different Intel-based
> computers (different generations), using 2 different webcams, same
> brand "same model".
>
> Is Logitech doing crappy hardware these days, or are we doing something
> wrong? Is there any way to know the reason that triggers the reset?

Is this before or after the uvcvideo driver gets involved ? One easy way
to check is to move the uvcvideo.ko module out of the way so that it
doesn't get loaded automatically (or just blacklist it in
/etc/modprobe.d/) and then plug the camera.

> I would be more than happy to provide any relevant debugging
> information if anyone is able to make it stop. As it stands, I must
> plug my webcam before using it and unplug it as soon as I'm done, which
> isn't exactly convenient.

-- 
Regards,

Laurent Pinchart

Re: Logitech C270 webcam floods the log

[Jean Delvare]

Hi Laurent,

Thank you very much for your quick reply and sorry for getting back to
you only today, your message got moved to a different folder by a
filter rule I did not remember of.

On Wed, 23 Oct 2019 17:20:16 +0300, Laurent Pinchart wrote:
> On Wed, Oct 23, 2019 at 03:18:59PM +0200, Jean Delvare wrote:
> > When my Logitech C270 webcam is plugged in, my kernel log gets filled
> > with this message:
> > 
> > usb 3-4.1: reset high-speed USB device number 4 using xhci_hcd
> > 
> > every 5 seconds. I have the same problem on 3 different Intel-based
> > computers (different generations), using 2 different webcams, same
> > brand "same model".
> >
> > Is Logitech doing crappy hardware these days, or are we doing something
> > wrong? Is there any way to know the reason that triggers the reset?  
> 
> Is this before or after the uvcvideo driver gets involved ? One easy way
> to check is to move the uvcvideo.ko module out of the way so that it
> doesn't get loaded automatically (or just blacklist it in
> /etc/modprobe.d/) and then plug the camera.

I did as you suggested and it turns out that the "reset high-speed USB
device" messages are not printed originally, they start being printed
right after the uvcvideo kernel driver gets loaded. So that would be a
problem with the uvcvideo driver?

When unloading the uvcvideo driver, there's one more "reset high-speed
USB device" message and then no more.

For what it's worth, 2 things worth noting in the kernel log when the
device is being detected:

usb 3-12: set resolution quirk: cval->res = 384
(...)
uvcvideo: Found UVC 1.00 device <unnamed> (046d:0825)

"<unnamed>" seems weird. On the other hand lsusb properly lists it as:

Bus 003 Device 004: ID 046d:0825 Logitech, Inc. Webcam C270

I an older C270 webcam (3 year old, different package) connected to
another machine, USB device ID is the same, I compared the verbose
output of lsusb and one difference stands out:

     Interface Descriptor:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       0
       bNumEndpoints           0
       bInterfaceClass        14 Video
       bInterfaceSubClass      2 Video Streaming
       bInterfaceProtocol      0 
       iInterface              0 
       VideoStreaming Interface Descriptor:
         (...)
-        bmaControls( 0)                    27
-        bmaControls( 1)                    27
-        bmaControls( 2)                    27
+        bmaControls( 0)                     0
+        bmaControls( 1)                     4
+        bmaControls( 2)                     4

(- is the new webcam, + is the old one)

I don't know if this tells anything useful though.

Thanks,
-- 
Jean Delvare
SUSE L3 Support

Re: Logitech C270 webcam floods the log

[Jean Delvare]

On Thu, 7 Nov 2019 14:39:41 +0100, Jean Delvare wrote:
> On Wed, 23 Oct 2019 17:20:16 +0300, Laurent Pinchart wrote:
> > Is this before or after the uvcvideo driver gets involved ? One easy way
> > to check is to move the uvcvideo.ko module out of the way so that it
> > doesn't get loaded automatically (or just blacklist it in
> > /etc/modprobe.d/) and then plug the camera.  
> 
> I did as you suggested and it turns out that the "reset high-speed USB
> device" messages are not printed originally, they start being printed
> right after the uvcvideo kernel driver gets loaded. So that would be a
> problem with the uvcvideo driver?
> 
> When unloading the uvcvideo driver, there's one more "reset high-speed
> USB device" message and then no more.

One more data point: the log flood happens when the uvcvideo driver is
loaded but the webcam is unused. If I start e.g. cheese, it takes a
long time to start but once started, the log flood stops. As soon as I
stop cheese, the log flood starts again.

-- 
Jean Delvare
SUSE L3 Support

Re: Logitech C270 webcam floods the log

[Oliver Neukum]

Am Donnerstag, den 07.11.2019, 14:52 +0100 schrieb Jean Delvare:
> On Thu, 7 Nov 2019 14:39:41 +0100, Jean Delvare wrote:
> > On Wed, 23 Oct 2019 17:20:16 +0300, Laurent Pinchart wrote:
> > > Is this before or after the uvcvideo driver gets involved ? One easy way
> > > to check is to move the uvcvideo.ko module out of the way so that it
> > > doesn't get loaded automatically (or just blacklist it in
> > > /etc/modprobe.d/) and then plug the camera.  
> > 
> > I did as you suggested and it turns out that the "reset high-speed USB
> > device" messages are not printed originally, they start being printed
> > right after the uvcvideo kernel driver gets loaded. So that would be a
> > problem with the uvcvideo driver?
> > 
> > When unloading the uvcvideo driver, there's one more "reset high-speed
> > USB device" message and then no more.
> 
> One more data point: the log flood happens when the uvcvideo driver is
> loaded but the webcam is unused. If I start e.g. cheese, it takes a
> long time to start but once started, the log flood stops. As soon as I
> stop cheese, the log flood starts again.
> 

Hi,

try

usbcore.autosuspend=-1

on the kernel command line.

	Regards
		Oliver

Re: Logitech C270 webcam floods the log

[Jean Delvare]

On Thu, 07 Nov 2019 15:56:20 +0100, Oliver Neukum wrote:
> Am Donnerstag, den 07.11.2019, 14:52 +0100 schrieb Jean Delvare:
> > One more data point: the log flood happens when the uvcvideo driver is
> > loaded but the webcam is unused. If I start e.g. cheese, it takes a
> > long time to start but once started, the log flood stops. As soon as I
> > stop cheese, the log flood starts again.
> 
> try
> 
> usbcore.autosuspend=-1
> 
> on the kernel command line.

That did not help, I still get the USB reset message in a loop.

-- 
Jean Delvare
SUSE L3 Support