On 11 February 2016 at 10:13, Jon Hunter <jonathanh@xxxxxxxxxx> wrote: > > On 10/02/16 18:25, Ulf Hansson wrote: > > [snip] > >>>> Perhaps there's a way to allow the generic PM domain to control this >>>> by itself. If we for example used the struct device corresponding to >>>> the powergate driver, genpd could use it to distinguish between >>>> various instances of genpd structs..!? Maybe it would simplify the way >>>> to deal with removing domains? >>> >>> Yes, that would be ideal. However, would have require changing >>> genpd_init()? I am not sure how genpd would be able to access the device >>> struct for the powergate driver because we don't provide this via any >>> API I am aware of? And I am guessing that you don't wish to expose the >>> gpd_list to the world either. >>> >>> If there is an easy way, I am open to it, but looking at it today, I am >>> not sure I see a simple way in which we could add a new API to do this. >>> However, may be I am missing something! >> >> If we add a new __pm_genpd_init() API, that could require a struct >> device to be provided. That API will thus invoke the existing >> pm_genpd_init() but also deal with the extra things needed here. >> >> I would also allow such an API to return an error code. >> >> Correspondingly, pm_genpd_remove() could be required to be provided >> with a struct device. >> >> Existing users of pm_genpd_init() can then convert to >> __pm_genpd_init() whenever suitable. >> >> Of course, another option is just to add new member in the genpd >> struct for the struct *device. The caller of pm_genpd_init() could >> check it, but allow it to be NULL. Although, the pm_genpd_remove() API >> would require that pointer to the struct device to be set... >> >> What do you think? > > Yes, sounds good. May be it is simpler just to add a new member and let > the platform genpd driver handle it. > > I am wondering if in addition to pm_genpd_remove(), we then just have a > function called pm_genpd_remove_tail(), which allows you to pass the > struct device pointer and will remove the last pm-domain from the > gpd_list and return the genpd pointer if successful. Internally, it will > call pm_genpd_remove(). It seems to me that if there are nested > pm-domains, then we probably want to remove them starting from the tail > as opposed to the head. > > How does that sound? Why not make pm_genpd_remove() to behave as you describe for pm_genpd_remove_tail()? That's probably the only sane way to remove genpds anyhow!? Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
