> -----Original Message----- > From: Felipe Contreras [mailto:felipe.contreras@xxxxxxxxx] > Sent: Tuesday, October 26, 2010 12:03 PM > To: Guzman Lugo, Fernando; felipe.contreras@xxxxxxxxx > Cc: gregkh@xxxxxxx; hiroshi.doyu@xxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; andy.shevchenko@xxxxxxxxx; > linux-omap@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Subject: RE: [PATCH 8/8] staging: tidspbridge - make > sync_wait_on_event interruptible > > fernando.lugo@xxxxxx wrote: > > > On Tue, Oct 26, 2010 at 3:51 AM, Fernando Guzman Lugo > > > <x0095840@xxxxxx> wrote: > > > > So that avoid non-killable process. > > > > > > It would be useful to interrupt these tasks from user-space. > > > A separate ioctl to do that would be needed. > > > > I don't see use case where that could be needed. It is only > To avoid a > > nonkillable task in the case the user pass an infinite Timeout. > > > > If you have some test case where that ioctl would be needed Please > > share it in order to find the best solution. > > Well, imagine the application is using a library to access > the DSP, and the library has a dedicated thread listening for > DSP events in a loop. > This happens to be how libomxil-ti and gst-dsp work. > > Now, the thread received the last message, but has set a > timeout of 10s, or even worst, no timeout at all. > > After realizing that was the last message, the main thread > decides to shut down, but it has to wait for the DSP thread > to join. Unfortunately the DSP thread is stuck waiting for > events, and there's nothing that can be done. > > However, if we have a separate ioctl to interrupt that task, > then the main thread can issue that ioctl, and unlock the DSP > thread without having to wait 10s, or forever. > > Does that make sense? Maybe sending a signal to yourselft and having a dummy signal Handle should work, it that would not like good. I am thinking On having a ioctl to create and set an event the you could Something like this: struct dsp_notification events[3]; proc_register_notify(proc, event_type, &events[0]); ... proc_register_notify(proc, event_type, &events[1]); ... Sync_open_event(&events[2]); second thread: mgr_wait_for_bridge_events(proc, events, 3, index); if (index == 2) /* main thread force exit */ Main thread: /* if some execption happened then finish the second thread */ sync_set_event(events[2]); pthread_join(...); However it is in progess a task for change replacing dspbridge sync.c Module with event_fd to signal events to userspace. Where now simple File descriptor will be used as event elements. So the mgr_wait_for_bridge_events Will be implemented using "select" system call inside to wait for multiple events. So you will be able to do something like this: int events[3]; proc_register_notify(proc, event_type, &events[0]); ... proc_register_notify(proc, event_type, &events[1]); ... events[2] = eventfd(0, 0); second thread: mgr_wait_for_bridge_events(proc, events, 3, index); if (index == 2) /* main thread force exit */ Main thread: /* if some execption happened then finish the second thread */ write(events[2], "s", 1); pthread_join(...); You won't need any aditional ioctl in order to do what you want to do. So, I think it is not worth to make much changes to some module that will Dissapear (my patch is just a fix it is not implementing something new), It is just a matter of time to that task is finished and tested properly And then send to LO. Regards, Fernando. > > -- > Felipe Contreras > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
