+ linux-pm On 04/18/2017 01:07 AM, Kishon Vijay Abraham I wrote: > Hi, > > resume_noirq callbacks are used in PCIe core to restore PCI state (this > accesses PCI module). So the clocks of PCI module has to be enabled before > resume_noirq. > > The clocks for the PCI module in DRA7xx is provided by PIPE3 PHY device which > in turn gets it's clock from OCP2SCP device. During resume_noirq callbacks, > pm_runtime is disabled, so pm_runtime_get_sync is ineffective. However > pm_runtime can be enabled using pm_runtime_force_resume. Now the problem is > adding pm_runtime_force_resume() in resume_noirq callback of pci-dra7xx driver > will enable only the pm_runtime of PCI device but not PIPE3 PHY or OCP2SCP. > Adding pm_runtime_force_resume() in resume_noirq callback of PIPE3 PHY driver > or OCP2SCP driver will not help if the resume_noirq callbacks in PIP3PHY driver > and OCP2SCP driver are invoked after the resume_noirq of pci-dra7xx driver. > > How to enable the pm_runtime of parent devices in resume_noirq callback? Does > existing pm_runtime framework has support for that? > Most probably you've hit the issue described in [1]. In general, if pci-dra7xx is consumer of PIPE3 PHY device and PIPE3 PHY device is child of OCP2SCP then suspend/resume order should be - pci-dra7xx - PIPE3 PHY - OCP2SCP and resume - OCP2SCP - PIPE3 PHY - pci-dra7xx and in this case pm_runtime_force_x() might work. Hence, approach [1] was not accepted (personally I still like it) and "Functional dependencies tracking support" was introduced instead by commit 9ed9895 [2] you can try it. But, as per code, I'm not sure that Functional dependencies properly tracked in pm_runtime_force_x() functions. PS: you can try to reorder device's nodes in DT and place PCI node after "ocp2scp" :P [1] "driver core: Ensure proper suspend/resume ordering" https://patchwork.kernel.org/patch/7153201/ [2] https://patchwork.kernel.org/patch/9404547/ -- regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
