Classic.
On Mon, Nov 9, 2009 at 3:22 PM, Remco den Breeje <[email protected]> wrote: > On Mon, Nov 9, 2009 at 2:06 PM, Jan Kiszka <[email protected]> wrote: >> The design. :) > > I totally agree :) However, I'm using generated (user-space) code that > I want to modify as little as possible. So with a simple ioctl-call I > want to be able to switch between software (pthread) and hardware > triggering (rtdm-driver). > >> The proper design is to use a rtdm semaphore or event *inside* the >> kernel and let the application block on it when it calls a related IOCTL >> or other device function that shall synchronize on that condition. >> >> Don't share resources like this between kernel and user space. It's >> unclean, specifically as you once may want to access driver managed data >> along the sleeping/waking as well. >> >> Jan > > The sem_open documentation states "a connection between the semaphore > named name and the calling context (kernel-space as a whole, or > user-space process)". I interpreted this as exactly what I want - a > synchronization between user- and kernel-space. Please correct me if > I'm wrong. > >> >> -- >> Siemens AG, Corporate Technology, CT SE 2 >> Corporate Competence Center Embedded Linux >> > > Attached you find an example. > You can run it by executing: `make && sudo insmod ./km.ko && sudo ./um > ; sudo rmmod km` > > My syslog-output is: "Error opening clock semaphore (2)" > > Thanks, > > Remco den Breeje >
sem-sharing.tar.gz
Description: GNU Zip compressed data
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