Am Dienstag, den 10.07.2018, 00:27 +0200 schrieb Ulf Hansson: > > On 6 July 2018 at 18:46, Leonard Crestez <leonard.cres...@nxp.com> wrote: > > On imx6qp power gating on the PU domain is disabled because of errata > > ERR009619. However power gating during suspend/resume can still be > > performed. > > Sounds a bit hand wavy. Exactly why can it be done during system > suspend/resume?
Power gating this domain in normal operation may introduce a glitch in unrelated modules, potentially disturbing a running display scanout. This is not a concern when the whole system enters suspend state, so it's safe to do in this case. Regards, Lucas > > > > Enable this by implementing SLEEP_PM_OPS in imx_pgc_power_domain_driver. > > > > In order to ensure correct ordering add device links from devices inside > > the PU domain to the pgc platform_device. > > In genpd, the PM domain gets powered off after all device's > corresponding ->suspend_noirq() callback has been invoked - and it > also considers if there are some wakeup settings enabled, possibly > avoiding to do the power off. > > It sound like the imx's power domain driver ->power_off|on() callback > should deal with this, to make get a consistent behavior. I understand > that you currently can't tell under what circumstances the > ->power_off|on() callbacks are being invoked, that may need some > changes in genpd. > > Currently we have a flag, GENPD_FLAG_ALWAYS_ON which makes genpd to > always prevent power off. Perhaps we should add a new flag > "GENPD_FLAG_RUNTIME_ON", which makes genpd to call the > ->power_on|off() callbacks, but only during system wide PM. > > Thoughts? Yes, this might work for this case. Regards, Lucas
