On Tue, Sep 09, 2014 at 09:01:08PM +0200, Ulf Hansson wrote: > [...] > > >> > + is_off = IS_ENABLED(CONFIG_PM_RUNTIME); > >> > + if (is_off) > >> > + imx6q_pm_pu_power_off(&imx6q_pu_domain.base); > >> > >> Could you elaborate why is_off depends on CONFIG_PM_RUNTIME? That > >> seems strange to me. :-) > >> > >> Additionally, I think it would be better to leave the domain "on" > >> state. Wouldn't that even be required for some drivers to be able to > >> succeed probing of these devices? > > > > The devices in the PU power domain are Vivante GPUs and the CODA Video > > Processing Unit. These are platform devices that don't need to be active > > to enumerate before being probed. The drivers support runtime PM, so if > > CONFIG_PM_RUNTIME is enabled, it is safe to disable the PU power domain > > on boot. The drivers will probe and request for the power domain to be > > enabled via runtime PM before accessing the hardware. > > > > If CONFIG_PM_RUNTIME is disabled, the power domain needs to stay enabled > > at all times. > > Hi Philipp, > > Thanks for your reply, that certainly made it clear on what you would > like to accomplish. > > Before discussing further consequences in genpd of this approach > (using IS_ENABLED(CONFIG_PM_RUNTIME)), I would be interested to see > how the runtime PM support is implemented for any of the drivers you > refer to. Do you mind pointing me to any of them? Of course, the CODA driver is at drivers/media/platform/coda.c in mainline kernels (moved to drivers/media/platform/coda-common.c in linux-next). regards Philipp -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
