Hi everybody, I'm developing a Linux driver for a Logitech USB webcam. A few users reported that the webcam stopped responding under some conditions. After some investigation, I found out that the device either timed-out or returned a STALL handshake during a control transfer on endpoint 0.
Logitech has been kind enough to investigate the problem. It seems a hardware bug is triggered when the control transfer transactions are sent "too fast". Preliminary results show that the hardware misses the second transaction in a control transfer when both the SETUP and IN/OUT transactions are in the same USB frame. I was wondering if anyone has ever seen such behaviour with other devices. It seems the bug is never triggered when using Microsoft Windows, so I suspect that Linux uses a faster scheduler. Is there a way to hack the USB scheduler to make it split control transfers across USB frames ? We would like to test if the hardware bug would then be still triggered. Cheers, Laurent Pinchart ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
