On Fri, 15 Feb 2013 00:58:23 +0800, Haojian Zhuang <haojian.zhu...@linaro.org> wrote: > On 15 February 2013 00:50, Arnd Bergmann <a...@arndb.de> wrote: > > On Thursday 14 February 2013, Haojian Zhuang wrote: > >> On 14 February 2013 23:57, Arnd Bergmann <a...@arndb.de> wrote: > >> > On Thursday 14 February 2013, Haojian Zhuang wrote: > >> >> If you can change it into code in below, it could work. Otherwise, it > >> >> always fails. > >> >> driver_deferred_probe_enable = true; > >> >> driver_deferred_probe_trigger(); > >> >> + deferred_probe_work_func(NULL); > >> >> return 0; > >> >> > >> >> Because deferred_probe_work_func() depends on that deferred_probe is > >> >> added > >> >> into deferred_probe_active_list. If driver_deferred_probe_trigger() > >> >> isn't called > >> >> first, the deferred uart probe can't be added into active list. So even > >> >> you call > >> >> work_func at here, it doesn't help. > >> >> > >> > > >> > Would that not cause two instances of the work function to run at the > >> > same time? > >> > That sounds like a source for a lot of problems. > >> > > >> > Arnd > >> > >> Two instances of the work function? I'm sorry that I don't > >> understanding your meaning. > >> Could you help explain your question? > > > > I mean you end up calling the work function directly, while it gets run as > > part > > of the work queue on a different CPU at the same time. I just noticed that > > there is actually locking in place in deferred_probe_work_func that prevents > > any actual bugs, but you are still adding extra overhead here. > > > > Maybe just add > > > > flush_workqueue(deferred_wq); > > > > here? > > > > Arnd > > It's fine to me. Since both of them are flushing workqueue. > > Tested-by: <haojian.zhu...@linaro.org>
Hahaha. I just came to the same conclusion. I'll craft a proper patch and send it off. g. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
