On Wed, 13 Apr 2005, Shiju Mathew wrote: > Hi Alan, > Here is the dmesg while the problem happens . The problem could be > easily reproduced on running the three instances of opening and > reading the status of cdrom device. On starting the third instance, > the ioctls calls of one of the first two instance will block until one > other instant is stoped. Looks like more than two instances of > opening and reading of usb cdrom fails.
The dmesg log wasn't helpful. It just showed a long sequence of TEST UNIT READY commands, possibly the result of your device-status ioctls. It would be helpful to see which commands correspond to which ioctl calls. You could do this by making your program sleep for, say, 15 seconds between ioctls. Also have it send a message to the system log immediately before doing the ioctl and immediately afterward, and include in those messages an identification saying which instance is running. Be sure to set up your /etc/syslog.conf so that the kernel debug-level messages are captured to a file along with the messages from your program. > As I mentioned before my > cdrom(RW DVD) is connected to a hub which inturn is connected to the > system usb port connected to the root hub. The presence of an intermediate should make absolutely no difference. If you think it's important, try running your test with the drive plugged directly into the computer. Alan Stern ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
