Messages in this thread | | | Date | Sat, 9 Mar 2002 03:46:18 +0000 (GMT) | From | Mark Cooke <> | Subject | Re: pwc-webcam attached to usb-ohci card blocks on read() indefinitely. |
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Just as a FYI, I had similar trouble using usb-uhci (440BX chipset) to a 680K using pwc/pwcx. I had to add a bunch of error recovery (close / open device, ignore open() failing and retry, etc).
I get a group of EMC messages logged , then the reset seems to take quite a while.
(2.4.19-pre2-ac2, but have seem this will many recent 2.4.x kernels)
Mark
On Fri, 8 Mar 2002, Thomas Winischhofer wrote:
> > The camera attached to the UHCI-controller running usb-uhci works just > > fine,out the three attached to the OHCI-controllers running usb-ohci don't. > > After a random amount of frames being read from a camera the read()-call > > blocks indefinitely until the device is closed. Next time the v4l-device is > > opened the program can again read frames from the camera but read() always > > blocks after some time. > > I can't help, but I have the exact same problem here. Closing the > application (eg. camstream) and re-opening it makes it work again for a > while. > > As Carl-Johan said, this happens with or without the pwcx module, so > that's not the problem. > > I think it's an ohci problem. > > Furthermore, the usb driver(s) behave strangely on > connecting/disconnecting the camera. Sometimes this works flawlessly, > sometimes I get a lot of USB timeout ("usb_control/bulk_msg: timeout") > and/or "USBDEVFS_CONTROL failed dev x rqt 128 rq 6 len 490 ret -110" > messages in the syslog. (Kernel is 2.4.16 and 2.4.18 - no difference) > After a couple of times disconnecting and reconnecting the camera it's > being detected. Since 2.4.18, the camera's LED sometimes is on, > sometimes off - seems quite random. > > Even closing the cam application (xawtv, camstream) after the camera > stopped working never results in any error messages in the log, I only > read "pwc: Closing video device: xxx frames received, dumped 0 frames, 0 > frames with errors" > > Thomas > >
-- +-------------------------------------------------------------------------+ Mark Cooke The views expressed above are mine and are not Systems Programmer necessarily representative of university policy University Of Birmingham URL: http://www.sr.bham.ac.uk/~mpc/ +-------------------------------------------------------------------------+
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