Hi Thomas, On Wed, May 26, 2010 at 19:04:40, Thomas Lange wrote: > Short version: > mmap does not work for me. I don't think data cache is flushed > before and after user space process runs which makes kernel and > user space see different data due to dirty cache lines. > > Long version: > I could not get mmap to work properly on my davinci board. > I have narrowed the problem down to a simple test case that > fails every time on my EVM6446 board. > > Test code attached along with console test logs. > I would be happy to get confirmation that I have implemented > the mmap driver correctly and that the problem really is with > the kernel itself. > > Test description > ---------------- > 1) Kernel module sets a variable in mmap:ed structure. > 2) Module awakens user space process. > 3) User space sees the _old_ data in mmap:ed structure. > 4) User space calls a system function (syslog). > 5) Now user space see the updated data. >
What is the reason for exposing the kernel data structure to userspace though mmap? Typically it is only used for IO data. Thanks, Sekhar _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
