On Sun, Mar 4, 2012 at 8:55 PM, Rafael J. Wysocki <[email protected]> wrote:
> A runtime suspend of an MMC controller belonging to a power domain > or, in a more complicated scenario, a runtime suspend of another > device in the same power domain, may cause power to be removed from > the entire domain. In that case, the amount of time necessary to > runtime-resume the MMC controller is often substantially greater > than the time needed to enable its clock. That may hurt performance > in some situations, because user data may need to wait for the > controller to become operational, so we should make it possible to > prevent that from happening. > > For this reason, introduce a new sysfs attribute for MMC hosts, > pm_latency_limit_ms, allowing user space to specify the upper bound > of the time necessary to bring the (runtime-suspended) host up after > the resume of it has been requested. However, make that attribute > appear ony for the hosts whose drivers declare support for PM QoS by > populating the pm_qos member of struct mmc_host before registering > the host. > > Signed-off-by: Rafael J. Wysocki <[email protected]> Acked-by: Linus Walleij <[email protected]> Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
