Messages in this thread | | | Date | Wed, 4 Oct 2023 00:09:52 +0200 | Subject | Re: [PATCH v12 1/1] serial: core: Start managing serial controllers to enable runtime PM | From | Maximilian Luz <> |
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On 10/3/23 14:21, Tony Lindgren wrote: > * Tony Lindgren <tony@atomide.com> [231003 12:15]: >> Hi, >> >> * Maximilian Luz <luzmaximilian@gmail.com> [231003 11:57]: >>> A bad workaround is to disable runtime PM, e.g. via >>> >>> echo on > /sys/bus/serial-base/devices/dw-apb-uart.4:0/dw-apb-uart.4:0.0/power/control >> >> If the touchscreen controller driver(s) are using serdev they are >> children of the dw-apb-uart.4:0.0 and can use runtime PM calls to >> block the parent device from idling as necessary. The hierarchy >> unless changed using ignore_children. > > Sorry about all the typos, I meant "the hierarchy works unless changed" > above. The rest of the typos are easier to decipher probably :)
Unfortunately that doesn't quite line up with what I can see on v6.5.5. The serdev controller seems to be a child of dw-apb-uart.4, a platform device. The serial-base and serdev devices are siblings. According to sysfs:
/sys/bus/platform/devices/dw-apb-uart.4 ├── driver -> ../../../../bus/platform/drivers/dw-apb-uart ├── subsystem -> ../../../../bus/platform │ ├── dw-apb-uart.4:0 │ ├── driver -> ../../../../../bus/serial-base/drivers/ctrl │ ├── subsystem -> ../../../../../bus/serial-base │ │ │ └── dw-apb-uart.4:0.0 │ ├── driver -> ../../../../../../bus/serial-base/drivers/port │ └── subsystem -> ../../../../../../bus/serial-base │ └── serial0 ├── subsystem -> ../../../../../bus/serial │ └── serial0-0 ├── driver -> ../../../../../../bus/serial/drivers/surface_serial_hub └── subsystem -> ../../../../../../bus/serial
Runtime suspend on serial0-0 is disabled/not set up at all. So I assume that if it were a descendent of dw-apb-uart.4:0.0, things should have worked out-of-the-box.
Regards, Max
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