On 31 May 2018 at 11:14, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote: > On 29-05-18, 12:04, Ulf Hansson wrote: >> Changes in v2: >> - Addressed comments from Geert around DT doc. >> - Addressed comments from Jon around clarification of how to use this >> and changes to returned error codes. >> - Fixed build error in case CONFIG_PM was unset. >> >> There are devices that are partitioned across multiple PM domains. Currently >> these can't be supported well by the available PM infrastructures we have in >> the kernel. This series is an attempt to address this. >> >> The interesting parts happens from patch 5 an onwards, including a minor DT >> update to the existing power-domain bindings, the 4 earlier are just trivial >> clean-ups of some related code in genpd, which I happened to stumble over. >> >> Some additional background: >> >> One existing case where devices are partitioned across multiple PM domains, is >> the Nvida Tegra 124/210 X-USB subsystem. A while ago Jon Hunter (Nvidia) sent a >> series, trying to address these issues, however this is a new approach, while >> it re-uses the same concepts from DT point of view. >> >> The Tegra 124/210 X-USB subsystem contains of a host controller and a device >> controller. Each controller have its own independent PM domain, but are being >> partitioned across another shared PM domain for the USB super-speed logic. >> >> Currently to make the drivers work, either the related PM domains needs to stay >> powered on always or the PM domain topology needs to be in-correctly modelled >> through sub-domains. In both cases PM domains may be powered on while they >> don't need to be, so in the end this means - wasting power -. >> >> As stated above, this series intends to address these problem from a PM >> infrastructure point of view. More details are available in each changelog. >> >> It should be noted that this series has been tested on HW, however only by using >> a home-cooked test PM domain driver for genpd and together with a test driver. >> This allowed me to play with PM domain (genpd), runtime PM and device links. >> >> Any further deployment for real use cases are greatly appreciated. I am happy to >> to help, if needed! > > Reviewed-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx> Thanks! 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
