usb host controller suspend

Andrey Rublyov

Prodigy 185 points

Other Parts Discussed in Thread: DM3730

Hi,

Is it possible to suspend usb host controller during runtime, not only PM suspend? I want to be called e.i.

ehci_omap_dev_suspend/ehci_omap_dev_reasume.

Is there any entry in fs for such things?

kernel: 2.6.37

board: omap3evm rev G

DM3730

Regards,

Andrey

over 13 years ago

0 Ajay over 13 years ago

TI__Genius 9460 points

You can refer Documentation/usb/power-management.txt for details.

It can be done using;

1) go to /sys/bus/usb/devices/usbX/power

2) echo auto > level

Ajay

0 Andrey Rublyov over 13 years ago in reply to Ajay

Prodigy 185 points

Thank you.

One more question. Usb host pwrdm does not hit ret/off during idle - of course it manage to achieve the proper state during sleep.

I took a look at srcs and I'm not sure but clocks are cut only when the host is suspended so - cpu idle mechanism (the loop) doesn't have

an influence on usb host. Doesn't it?

0 Ajay over 13 years ago in reply to Andrey Rublyov

TI__Genius 9460 points

I understand it is not supported. You can enable CONFIG_USB_SUSPEND and let usb stack switch off the clock from usb perspective wheevr it detects idle condition and if "level" is set to "auto".

Ajay

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usb host controller suspend