Am 20. September 2021 09:31:20 MESZ schrieb Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>: >On 17.09.21 18:10, Heiko Thiery wrote: >> Hi Lucas, >> >> Am Fr., 17. Sept. 2021 um 13:44 Uhr schrieb Lucas Stach >> <l.stach@xxxxxxxxxxxxxx>: >>> >>> Am Freitag, dem 17.09.2021 um 09:28 +0200 schrieb Heiko Thiery: >>>> Hi Frieder, >>>> >>>> Am Mi., 15. Sept. 2021 um 14:09 Uhr schrieb Frieder Schrempf >>>> <frieder.schrempf@xxxxxxxxxx>: >>>>> >>>>> On 15.09.21 14:05, Michael Walle wrote: >>>>>> Am 2021-09-15 14:03, schrieb Heiko Thiery: >>>>>>> The buck2 output of the PMIC is the VDD core voltage of the cpu. >>>>>>> Switching off this will poweroff the CPU. Add the 'regulator-always-on' >>>>>>> property to avoid this. >>>>>> >>>>>> Mh, have this ever worked? Is there a commit which introduced a regression? >>>>> >>>>> Yes, this did work before, even without 'regulator-always-on'. I >>>>> currently don't understand why this is needed. The regulator is >>>>> referenced in the CPU nodes as 'cpu-supply'. This should be enough to >>>>> not disable it as long as the CPU is up. >>>> >>>> I rechecked that with 5.11, 5.10 and 5.9 and I see on all of them the >>>> same issue: >>>> >>>> [ 31.716031] vdd-5v: disabling >>>> [ 31.719032] rst-usb-eth2: disabling >>>> [ 31.722553] buck2: disabling >>>> >>>> While on that I tried to compare with other boards and see that they >>>> also have the cpu-voltage marked as "regulator-always-on". The only >>>> exception in dts/freescale is in imx8mq-librem5-devkit.dts [1] that >>>> has not set this property. >>>> >>>> I agree with you and don't understand why this is happening. Has >>>> anyone else an explanation? >>>> >>>> [1] https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Flatest%2Fsource%2Farch%2Farm64%2Fboot%2Fdts%2Ffreescale%2Fimx8mq-librem5-devkit.dts%23L319&data=04%7C01%7Cfrieder.schrempf%40kontron.de%7Cce9d266ad78a4d06721008d979f5aeed%7C8c9d3c973fd941c8a2b1646f3942daf1%7C0%7C0%7C637674918380815550%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=PsTKX4MXGwvvP6WxmQ1OWc8e32YI6Nsu%2FEkcNR4V8is%3D&reserved=0 >>>> >>> Maybe your kernel config is missing the cpufreq driver, so you don't >>> have a consumer of the regulator? >>> >>> Marking the regulator as always-on seems like the right thing to do, >>> you don't want to depend on a consumer showing up to make sure that >>> your CPU voltage isn't cut... >> >> shouldn't it be that the node cpu-supply here is a consumer of the >> referenced voltage? > >Yes, but as Michael and Lucas noted, the consumer is only active if the >cpufreq driver is loaded and we don't want to depend on this. In my >config I always had this compiled into the kernel so I didn't notice >that the always-on property is missing. Hm. So any cpu core voltage has to have the "always-on" property? On any SoC? Shouldn't there be some code to prevent the disabling of the voltage if the cpu nodes have a cpu-supply phandle? -michael
