2010/8/9 Rafael J. Wysocki <rjw@xxxxxxx>: > On Monday, August 09, 2010, Arve Hjønnevåg wrote: >> 2010/8/8 Rafael J. Wysocki <rjw@xxxxxxx>: >> > On Saturday, August 07, 2010, Arve Hjønnevåg wrote: >> >> 2010/8/7 Arve Hjønnevåg <arve@xxxxxxxxxxx>: >> >> > 2010/8/7 Rafael J. Wysocki <rjw@xxxxxxx>: >> >> >> On Saturday, August 07, 2010, Arve Hjønnevåg wrote: >> >> >>> 2010/8/6 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>: >> >> >>> > On Thu, 5 Aug 2010, Arve Hjønnevåg wrote: >> >> ... >> >> >>> >> total_time, total time the wake lock has been active. This one should >> >> >>> >> be obvious. >> >> >>> > >> >> >>> > Also easily added. >> >> >>> > >> >> >>> Only with a handle passed to all the calls. >> >> >> >> >> >> Well, I'm kind of tired of this "my solution is the only acceptable one" >> >> >> mindset. IMHO, it's totally counter productive. >> >> >> >> >> > >> >> > How do you propose to track how long a driver has blocked suspend when >> >> > you have an unblock call that takes no arguments. >> >> > >> >> >> >> Also, I did not not see a response to my question about why you don't >> >> want to pass a handle. >> > >> > It doesn't really matter what I personally want. In fact, I'm not totally >> > opposed to that idea, although there are disadvantages (eg. a "handle" >> > would really mean a pointer to an object with certain life cycle that needs to >> > be managed by the caller and it's not that clear to me who should manage the >> > objects that the PCI wakeup code would pass to pm_wakeup_event(), for one >> >> Wouldn't a single global handle work for the way you are handling pci >> wakeup events? > > Not really, because I'd like to know the number of wakeups associated with > the given device. > For debugging purposes right? I'm not sure automatically counting wakeup events from pm_stay_awake and pm_wakeup_event is the best way to do this. To avoid race conditions these calls have to be made for every event that could also be a wakeup event, which means the actual wakeup event easily gets lost in the noise. This is why I had a separate wakeup count that only increments on the fist call to wake_lock after each suspend, but this did not work that well either. >> It looked like you just reset a global timeout every time a pci wakeup event >> occurs. > > We bump up the per-device counter of wakeup events in addition to that. > >> > example). I sent a pull request for your original patchset to Linus after all. :-) >> > >> > I said I didn't think "it would fly", meaning that I was afraid the other kernel >> > developers wouldn't like that change. >> > >> > The reason why I think so is that you'd like to add a whole new infrastructure >> > whose only purpose would be debugging that would only be useful to systems >> > using opportunistic suspend. That, however, is only Android right now and it >> > cannot use the mainline kernel for other reasons, so basically we would add >> > infrastructure that's useful to no one. >> > >> >> I'm not sure what you mean by this. The debugging is useful for anyone >> using the api, not just Android, and a handle is also needed to mix >> timeouts and pm_relax. > > The purpose of the debugging would be to be able to figure out why the system > is staying in the working state, which is only relevant for systems that use > opportunistic suspend. > Only if the drivers do not have bugs. A driver calling pm_say_awake without a matching pm_relax call will prevent any race free suspend from succeeding. > If opportunistic suspend isn't used, it makes sense to ask which > device caused suspend (initiated by the user) to be aborted and for this > purpose it is sufficient to count wakeup events associated with each > device (you need to preserve the pre-suspend values of these counters, but > that can be done by a user space power manager just fine). > >> The handle can be the device, but some drivers need several handles per >> device. > > That depends on how precise the collected debug information should be and > that, in turn, depends on what it's going to be used for. > It is not just debug information. Drivers that mix wake_lock_timeout and wake_unlock do not map to the current api. > Anyway, as I said I'm not opposed to the idea of using a special type of > objects for collecting debug information on wakeup events, so please free to > submit patches modifying the current mainline kernel code in that direction. > How do you prefer to handle your pci wakeup events? Add a handle to every device or pci device? Or use a global handle to avoid the race and report wakeup events for debugging separately? -- Arve Hjønnevåg _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
