On Friday, October 08, 2010, you wrote: > > Hi Rafael, Hi, > I am working on device driver whose some part is user space and some part is kernel space. So the user space part > of the driver provides interface to user space applications. > 1) Now, Suppose some user space is application is going on which is accessing the user space driver and user space driver > scheduled some jobs to kernel space, Now suppose system hibernation start, since it freezes all the user space processes > so suppose jobs are not completed yet which are scheduled to kernel space by user space. > > when the kernel space device driver completes the jobs and gives the notification to user space driver, since user space > process is already frozen, so there will be problem if we suspend the driver using suspend and resume. > > right? Yes, there's going to be a problem if the driver is not prepared to handle such situations. Depending of the particular case, one possible approach is to use a PM notifier as described in Documentation/power/notifiers.txt. > 2) The other point I was seeing, when the power management core freezes all the processes before suspending and resuming > devices, it will take some time for freezing and after that if some device driver refuses to suspend, then it will again resume > the whole processes, so latency time be more. right? Yes, it works as described. > 3) Next question is regarding the kernel space threads, when these are frozen during suspend/hibernation? They are frozen immediately after user space has been frozen, but only a handful of kernel threads are frozen. Thanks, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
