| Message ID | 20250115113931.1181309-1-sudeep.holla@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | pmdomain: arm: scmi_pm_domain: Send an explicit request to set the current state | expand |
diff --git a/drivers/pmdomain/arm/scmi_pm_domain.c b/drivers/pmdomain/arm/scmi_pm_domain.c index a7784a8bb5db..86b531e15b85 100644 --- a/drivers/pmdomain/arm/scmi_pm_domain.c +++ b/drivers/pmdomain/arm/scmi_pm_domain.c @@ -96,6 +96,14 @@ static int scmi_pm_domain_probe(struct scmi_device *sdev) continue; } + /* + * Register the explicit power on request to the firmware so + * that it is tracked as used by OSPM agent and not + * accidentally turned off with OSPM's knowledge + */ + if (state == SCMI_POWER_STATE_GENERIC_ON) + power_ops->state_set(ph, i, state); + scmi_pd->domain = i; scmi_pd->ph = ph; scmi_pd->name = power_ops->name_get(ph, i);
On a system with multiple active SCMI agents, one agent(other than OSPM/ Linux or bootloader) would request to turn on a shared power domain before the Linux boots/initialise the genpds. So when the Linux boots and gets the power state as already ON, it just registers the genpd with a default ON state. However, when the driver that needs this shared power domain is probed genpd sees that the power domain status is ON and never makes any SCMI call to power it up which is correct. But, since Linux didn't make an explicit request to turn on the shared power domain, the SCMI platform firmware will not know if the OSPM agent is actively using it. Suppose the other agent that requested the shared power domain to be powered ON requests to power it OFF as it no longer needs it, the SCMI platform firmware needs to turn it off if there are no active users of it which in the above scenaro is the case. As a result of SCMI platform firmware turning off the resource, OSPM/ Linux will crash the moment as it expects the shared power domain to be powered ON. Send an explicit request to set the current state when setting up the genpd power domains so that OSPM registers its vote in the power domain state with the SCMI platform firmware. The other option is to not read the state and set the genpds as default OFF, but it can't handle the scenario on certain platforms where SCMI platform keeps all the power domains turned ON by default for faster boot (or any other such variations) and expect the OSPM to turn off the unused domains if power saving is required. Cc: Ulf Hansson <ulf.hansson@linaro.org> Link: https://lore.kernel.org/all/Z4aBkezSWOPCXcUh@bogus Reported-by: Ranjani Vaidyanathan <ranjani.vaidyanathan@nxp.com> Reported-by: Peng Fan <peng.fan@nxp.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> --- drivers/pmdomain/arm/scmi_pm_domain.c | 8 ++++++++ 1 file changed, 8 insertions(+) Hi Ulf, We need your feedback or suggestions for better solution on this matter. Let us know if we can do something better with the genpd's help to resolve this issue. Regards, Sudeep