On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote: > On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@xxxxxx> wrote: > > On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote: > >> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote: > >> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote: > > [....] > > >> > > >> > With this patch, will you be able to choose gptimer as a clocksource > >> > using bootparameter (or sysfs) for given kernel uImage? > >> > > >> Why do you want that ? Look at changelog. The gptimer based clocksource > >> is useless for OMAP and for AM devices synctimer is not available. > >> > >> > >> > The answer is simply NO...as the registration of gptimer is based on > >> > failure from omap_init_clocksource_32k(). And this is nothing different > >> > than my original patch, my patch exactly does same thing. > >> > > >> I ight have missed your original patch. If that patch is similar then > >> no problems. > >> > >> > The requirement after 'ming Lie' response on my patch was, there will be > >> > usecases where we might need to use gptimer for clocksource and with > >> > the patch it is not possible, since you will only register > >> > 32k_counter here. > >> > > >> I think Ming Lie might have expected that gptimer clocksource might > >> be better which is not the case. > >> > >> > So in order to allow user to choose between 32K and gptimer, you must > >> > register both and make 32k as a default thing. > >> > > >> As described in the commit log, its not needed at all. Let's not add > >> a feature which is just useless because the gptimer based clock > >> source has no advantage against the syntimer. > >> > > > > I completely agree with you, and that is my understanding too. > > > Thanks !! > > > After Ming Lie's comment, the point that I came to my mind was, > > certainly there will be resolution difference between these two clocksources, > > if gptimer2 is sourced from sys_ck (26Mhz). > > > GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain > and when sysclock is cut, it stops. > > > I am quite not sure, whether will there be any practical usecase where you > > change the kernel clocksource for high resolution dynamically through sysfs > > or something. May be not....but still it is possible. > > > Even if there is a usecase, there no option with full PM. > What if before suspending the system, you switch back to 32k_counter everytime, and in resume you again switch to gp_timer? Please consider this as just a technical discussion, as I am myself quite not sure whether we have such use-case available. > > > > In that case my original patch still holds good here. I would still request > > you to review the same and give your acked-by or tested-by. > > > I just looked at that. > It looks fine to me. Can you repost that patch addressing Kevin and > Tony's comments. > Also update the change log as describe in the patch i posted. > > Once that done, will ack it. > Thanks for the review and discussion, I will submit revised version shortly. Thanks, Vaibhav -- 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
