> -----Original Message----- > From: Felipe Contreras [mailto:felipe.contreras@xxxxxxxxx] > Sent: Tuesday, October 26, 2010 2:27 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: > > > 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. > > Signals on libraries is a no-no. > > > 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. > > All right, that makes sense. I just wanted to make suere you > are aware of that need. Sure, that need will cover soon. Thanks and 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
